Good evening! Thank you very much for joining Sports Mole for tonight's Champions League Group D match between Olympiacos and Barcelona!

This could be a pivotal night in the Group D standings, with Barcelona looking to book their place in the last 16 and Olympiacos facing the prospect of being eliminated from the competition with two games still to spare. A win would do wonders for either side, but for very different reasons.

Before we get into all that, though, let's first check out the team news...

OLYMPIACOS STARTING XI: Proto; Elabdellaoui, Botía, Engels, Koutris; Tachtsidis, Romao, Odjidja; Carcela-Gonzalez, Figueiras, Fortounis

BARCELONA STARTING XI: Ter Stegen; Semedo, Mascherano, Umtiti, Alba; Busquets, Paulinho, Sergi Roberto; Messi, L Suarez, D Suarez

BARCELONA SUBS: Cillessen, Rakitic, Deulofeu, Alcácer, Digne, A Gomes, Vermaelen

What can we make of those two sides, then?

Well, we will get to the home side a little later, but let's start with Barcelona, who are missing a number of key players for this evening's match. Chief among them is Andres Iniesta, who picked up a thigh injury prior to the weekend win over Athletic Bilbao and has not recovered in time, while fellow stalwart Gerard Pique is suspended after picking up two yellow cards in the opening 42 minutes of the reverse fixture a fortnight ago.

The good news for Ernesto Valverde is that Javier Mascherano has been passed fit to cover for Pique, having initially been a doubt for this match.

There were also concerns over the fitness of Jordi Alba, but he starts again tonight having also been including in the lineup at the weekend. Nelson Semedo, who is just one booking away from a Champions League suspension, is on the opposite flank, meaning that Samuel Umtiti is the only survivor of the reverse fixture from that back four.

Whether Barca opt to line up in a 4-4-2 formation or a 4-3-3 formation remains to be seen - the former has been the most common since Dembele's injury, but Valverde went for the more attacking 4-3-3 option in the reverse.

The personnel selected suggests that it will be a 4-4-2, though, with Denis Suarez chosen ahead of the likes of Deulofeu, Alcacer and Gomes. Roberto looks set to play further forward than he did in the reverse fixture, while Paulinho - who has only been outscored by Messi in the Barcelona camp this season, retains his place in midfield.

In all there are only three changes from the weekend and four from the reverse.

Leading the line will, of course, be Luis Suarez and Lionel Messi, the latter of whom was on the scoresheet yet again at the weekend to make it 19 goals in as many games for club and country so far this season - although that was still enough for him to win The Best FIFA Men's Player award as he once again missed out to Cristiano Ronaldo.

Messi did, however, score his 100th goal in European competition in the reverse fixture a fortnight ago, and a hat-trick tonight would take him up to the century mark in the Champions League proper too.

© Offside

As for Olympiacos, their formation was always going to be interesting tonight having left Vadis Odjidja-Ofoe as their most advanced player for much of the match at the Camp Nou a fortnight ago.

It was an unfamiliar position for the midfielder, and sure enough he reverts back to his preferred role in the middle of the park tonight. That suggests Olympiacos will approach the game with a little more attacking intent, which they have to really considering their perilous position at the bottom of the group.

Olympiacos also welcome Botia back into the side, and it will be a particularly special night for him tonight as he faces his former club.

The Spanish centre-back has struggled with injury so far this season and has featured sparingly, but he was fit enough to captain the team at the Camp Nou and once again starts this evening after being an unused sub in the defeat to arch-rivals Panathinaikos at the weekend.

Botia joined Barcelona at the age of 14 and spent three years in their B side, but he made just one appearance for the senior team - a 1-1 draw with Deportivo in the final game of the 2008-09 season.

Botia, who was a teammate of Sergio Busquets in the B team, went on to enjoy spells in Spain with Sporting, Sevilla and Elche, while Diogo Figueiras is another former Sevilla player and was part of the squad that won the Europa League in 2013-14.

Mehdi Carcela-Gonzalez is another with experience of Spanish football, and he is currently on loan at Olympiacos from Granada.

The hosts have made five changes to the side that started at the weekend, with no Emmanuel Emenike in the starting XI despite his recent return to fitness.

There are also four changes to the side which took to the field for the start of the return leg, including no Nikolaou, who scored at both ends at the Camp Nou.

It looks like being a tough task for the hosts this evening, having failed to ever really trouble Barcelona a fortnight ago.

Not many people would have been expecting Olympiacos to get anything from the Camp Nou, but Gerard Pique's 42nd-minute red card should have given them a glimmer of hope - particularly as they were only one goal down at the time.

Olympiacos never built on the red card, though, and despite enjoying the numerical advantage for more than half the match, they were fortunate that the final deficit was only two goals in their 3-1 defeat - with their goal coming late one with the game already beyond them.

Takis Lemonis's side will be the underdogs again this evening, and in truth the Champions League may be a second priority for the club at the moment considering their relatively poor start to their domestic campaign.

To say that Olympiacos have dominated Greek football in recent seasons would be an understatement - they have won the last seven Super League titles and, incredibly, 19 of the last 21, including lifting the title for a record 44th time last season to once again qualify for the Champions League.

However, the champions currently sit fourth in the standings - a lowly position by their very high standards. There are only five points separating them from surprise leaders Atromitos, which is by no means an unassailable gap after nine games, but it has certainly been a slower start than many expected from Olympiacos.

The Thrylos lost just five league games throughout the entirety of last term, but they have already lost three of their nine outings this season, with just four wins to their name in that time too.

While domestic success has come to be expected for Olympiacos, Champions League success always looked like a much tougher ask this season having been drawn in a difficult group alongside Barcelona, Juventus and Sporting Lisbon.

It would have taken a few upsets for Olympiacos to beat one of Barca or Juve to a top-two spot, but third place and a Europa League spot would have been the realistic target. However, even that looks unlikely now following their 3-2 home defeat at the hands of Sporting on matchday one.

Subsequent defeats in Turin and Barcelona have left Olympiacos still searching for their first point of the campaign, and they could be eliminated from the competition if they don't pick that up this evening.

Defeat for Olympiacos would open up an unassailable gap to the top two should Juventus avoid defeat to Sporting in the group's other game, while even a draw against Barcelona would not be enough for tonight's hosts in Juve win in Lisbon.

Olympiacos have lost five of their last eight matches across all competitions, and counting just the league and the Champions League, they have only won two of their last 10 outings, losing six in that time - a dreadful run of form for a club of their calibre.

In the Super League alone they have lost three of their last five games and have only won two of their last seven, leaving them in the unfamiliar position of having to play catch-up.

Olympiacos have also only won one of their last four home games in the league and Champions League, although they did keep their first home clean sheet of the season in their most recent match at this stadium - a 1-0 triumph over high-flying PAOK.

Another victory tonight would make it back-to-back home wins for only the second time this season, but they have won just one of their last six European outings in front of their own fans and only three of their last 12 - including the matchday one defeat to Sporting.

A usually-daunting European away trip does not seem too bad for Barcelona tonight, then, although their own away record in Europe has not been the best in recent times either - certainly worse than one might expect from a team of their calibre.

Barca have lost three of their last five away Champions League games, conceding 10 goals and scoring just four in reply during that time - including a 4-0 loss at PSG and 3-0 defeat at Juventus last season. Indeed, stretching even further back, Barca have won just five of their last 12 Champions League outings on the road, suffering as many defeats in that time.

Ernesto Valverde's side have already beaten Sporting on the road in this season's competition - albeit only because of an own goal in their 1-0 victory - and another win tonight would make it back-to-back away Champions League wins for the first time since April 2015.

Barca will certainly go into the game as favourites having kept up their relentless form at the weekend, beating Athletic Bilbao 2-0 to maintain their four-point lead over Valencia at the top of the La Liga table.

Perhaps more importantly, Real Madrid's shock 2-1 defeat to Girona means that Barca now enjoy an eight-point lead over their fiercest rivals and defending champions having dropped just two points from their opening 10 games, boasting the best attack and best defence in the process.

It has been a similar story of dominance in this competition too, with three wins from three lifting them to the top of the group and leaving them on the brink of the last 16 at the halfway stage.

Barcelona would seal their place in the knockout rounds for a 14th consecutive season with a victory tonight should Juventus also fail to beat Sporting, while a draw could also be enough for Valverde's side if Sporting fail to beat Juventus - so a draw in Lisbon would be an ideal result for Barca tonight.

Of course, Valverde's side would still need to hold up their end of their bargain, but having won 13 and lost none of their last 14 matches across all competitions, they will be justifiably confident of doing that.

An away trip to Atletico Madrid's brand new Wanda Metropolitano Stadium is the only match Barcelona have failed to win since their back-to-back Super Cup defeats at the hands of Real Madrid, emphatically ended talk of a crisis at the club following the loss of Neymar and failure to land some big summer targets.

Instead, Barca are now favourites to win the league title back from Real Madrid and amongst the frontrunners to also succeed their fierce rivals as champions of Europe.

Barcelona have won six and drawn one of their seven away outings since their Super Cup loss at the Bernabeu, keeping five clean sheets in the process, while throughout their 14-match unbeaten streak they have stopped the opposition from scoring no fewer than 10 times.

Perhaps the biggest criticism of Luis Enrique's Barcelona, for all their success, was their defensive record, but Ernesto Valverde appears to have addressed that problem quickly since arriving.

On the subject of Valverde, this will be a particularly special occasion for him as he returns to one of his former clubs having enjoyed great success over two spells as Olympiacos boss.

Named as manager in 2008-09 and then again from 2010-12, Valverde led Olympiacos to three league titles and two Greek Cups during his time in charge and he is expected to be given a very warm reception by the home fans this evening.

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PREDICTION: Right, we're 10 minutes away from kickoff for this one, which means that it is time for a prediction!

Olympiacos should fare better tonight than they did at the Camp Nou, at least in terms of making a game of it. However, should they try to attack more then that could also play into the hands of Barcelona, and I am backing the visitors to come away with another victory tonight.

SPORTS MOLE SAYS: Olympiacos 0-2 Barcelona

The reverse fixture a fortnight ago was the first ever competitive meeting between these two sides, with Barcelona running out 3-1 winners at the Camp Nou despite having Pique sent off in the 42nd minute following his second yellow card for handling the ball into the net.

Messi was among the scorers, meaning that he has now found the back of the net in each of Barca's last four meetings with Greek opposition - all of which they have won.

Indeed, Barca have won 10 of their 13 fixtures against Greek clubs over the years, losing just twice and remaining unbeaten in their last seven - with six wins in that time too.

Away from home Barca are unbeaten in their last three, but both of their defeats have come on Greek soil. They also infamously lost the 1994 Champions League final in Athens, being swept aside by the great AC Milan team in a 4-0 defeat.

Olympiacos won their last home match against Spanish opposition, recording a 3-2 victory over Atletico Madrid in this competition three years ago, and their overall home record against La Liga teams is good.

The Thrylos have lost just two of their previous 14 home matches against clubs from Spain, winning six of those and drawing six too.

We are only a couple of minutes away from kickoff in Athens, so let me give you a quick recap of the team news ahead of this one...

OLYMPIACOS STARTING XI: Proto; Elabdellaoui, Botía, Engels, Koutris; Tachtsidis, Romao, Odjidja; Carcela-Gonzalez, Figueiras, Fortounis

BARCELONA STARTING XI: Ter Stegen; Semedo, Mascherano, Umtiti, Alba; Busquets, Paulinho, Sergi Roberto; Messi, L Suarez, D Suarez

KICKOFF: Premier League referee Anthony Taylor blows his whistle, and Olympiacos get us underway for this potentially pivotal Group D clash.

UPDATE: It hasn't taken long for the first goal to go in, and it is bad news for Chelsea - Roma are a goal ahead within the first minute at the Stadio Olimpico through Stephan El Shaarawy.

SAVE! Barcelona have made a confident start too, and Semedo is the first to have a shot which Proto has to parry away.

There have already been a couple of warning signs for Olympiacos, with Barcelona almost getting in behind. The hosts will need to be alert for the full 90 minutes if they are to keep the likes of Messi and Suarez quiet.

Barca break through again, but Suarez is well offside by the time he latches on to Paulinho's pass. It doesn't feel like the first goal is too far away, though.

Good work from Fortounis, who has been deployed as Olympiacos' most advanced player tonight. He will need to hold on to the ball at times tonight as he is likely to be isolated, and he does it well here before being fouled by Semedo.

Barca win a couple of corners in quick succession, but both of Messi's deliveries are well dealt with. The ball comes straight back at them, though. They have been unable to get hold of possession for any significant amount of time so far.

Busquets tries to clip a pass over the top for Alba, who just can't bring it under his spell. Barca have been almost permanent camped in the Olympiacos half so far, though.

UPDATE: Manchester United have had a penalty against Benfica, but Anthony Martial's strike has been saved! It remains goalless at Old Trafford, and indeed everywhere across Europe apart from Rome.

CHANCE! Chance for the hosts as Elabdellaoui is played through down the right channel, but Umtiti slides in and makes a sensational tackle, getting his toe to the ball just before the former Hull man.

Elabdellaoui goes down and asks for a penalty, but Anthony Taylor is having none of it, and rightly so. There was contact, but only after Umtiti had made that brilliant challenge.

That is the biggest scare for either side so far, and while Barcelona have been dominating possession so far, they will be desperate to break the deadlock sooner rather than later. Olympiacos are defending pretty well at the moment.

DISALLOWED GOAL! Barcelona have the ball in the back of the net, but Denis Suarez is correctly flagged offside. Messi slid a clever pass through and Suarez duly finished it, but he was a couple of yards off.

CHANCE! Almost the opener for Barcelona as Messi peels off his man from a corner, which is played low and deep into the box. It is all too easy, but Messi's contact is not up to his usual standard and it bobbles towards goals.

Suarez tries and fails to flick it on right in front of the keeper, but Proto just about makes the save. Not the cleanest stop, but it did the job.

CHANCE! Good chance for Barcelona as Suarez is slipped in down the left channel, but he tries to poke it towards goal with the outside of his right foot and puts it wide of the target.

UPDATE: Interesting news for the other game in this group tonight as Sporting have taken the lead against Juventus through Bruno Cesar.

Elsewhere, Kingsley Coman has broken the deadlock for Bayern Munich at Celtic Park.

Almost a calamitous moment between Umtiti and Ter Stegen as the defender waits for the goalkeeper, who in turn waits for the defender. Fortounis is lurking and Ter Stegen plays the ball against Umtiti, and Barcelona are fortunate that it rebounds out for a corner rather than anywhere more dangerous.

It's all very crowded in the Olympiacos half at the moment, which is making things very difficult for Barcelona. The visitors continue to dominate possession, but Olympiacos are making it a scrappy game and are holding their own right now.

CHANCE! It has taken some Messi magic to spark Barcelona into life a few times already this season, and again he almost grabs his team by the scruff of the neck here. He dribbles into the box with three of four Olympiacos defenders chasing after him, but his eventual shot is saved by Proto.

UPDATE: Still goalless here, but another one of the favourites for this competitions PSG have broken the deadlock at home to Anderlecht through Marco Verratti.

CHANCE! Half a chance for the hosts as Odjidja-Ofoe nods the ball back to Fortounis on the edge of the box, but he fires his effort over the crossbar when he should have done better.

Barcelona may have dominated possession so far tonight, but they have also been sloppier than we are used to seeing them at times. This is by no means a vintage Barca performance.

If Barcelona are going to make the breakthrough here, it is no surprise that Messi looks the most likely outlet. He embarks on another run here, but this time his effort is blocked.

Suarez goes down under the challenge of Botia, which gives Barca a free kick in a dangerous position. Messi and Suarez are standing over this one...

SAVE! Messi always seems to get free kicks on target, and he couldn't have placed this one much better. It is a long way out, though, and doesn't have the pace to beat Proto, who pushes it behind.

YELLOW CARD! Tachtsidis is the first name in the book tonight for a challenge from behind on Messi.

CHANCE! Olympiacos have had their sights of goal tonight, and this is the best of the lot so far. Again it falls to Fortounis, who flicks it towards goal at the end of a quick counter-attack, but it is straight at Ter Stegen.

UPDATE: Chelsea look to be losing their grip at the top of their group, with El Shaarawy doubling his personal tally to give Roma a 2-0 lead at the Stadio Olimpico.

Incredibly, Qarabag have also taken the lead away to Atletico Madrid in that group, while Basel now lead CSKA Moscow in Manchester United's group.

Another sight of goal for the hosts, although this one is an ambitious effort. Carcela tries his luck from a tight angle, but blazes it well off target.

YELLOW CARD! Sergi Roberto is the first Barcelona player in the book tonight for a shirt tug, but that may be the least of his worries as he appears to be struggling with a hamstring injury after that.

UPDATE: Hero to villain for young Benfica goalkeeper Mile Svilar - having saved a penalty earlier, he has just scored an own goal to give Manchester United the lead at Old Trafford.

There will be one minute of added time at the end of this first half.

BARCELONA SUB: Sergi Roberto is unable to continue here, and he is replaced by Gerard Deulofeu.

Anthony Taylor brings an end to the first half in Athens, and we are still all square at the interval between Olympiacos and Barcelona.

The visitors can have no complaints at that scoreline either, and Olympiacos may even feel that they should be ahead, despite giving up the lion's share of possession and shots. The stats don't paint an accurate picture of the match, though, with the hosts have held their own in this one.

Barca have been out of sorts so far tonight, with a lot of sloppy passing preventing them from getting into any sort of rhythm.

As you might expect, their best chances have come through Lionel Messi, who has twice been denied with Proto - once after peeling away from his man to meet a low corner and then at the end of a trademark solo run. Suarez has also had a decent sight of goal, although he failed to hit the target on that occasion.

The hosts have not exactly been pounding on the door at the other end, but they have had sights of goals and could realistically be ahead at the halfway stage.

Their best chances have fallen the way of Fortounis, who is playing as their most prominent attacker tonight, but he has blazed one effort off target when he should have done better before flicking another finish straight at Ter Stegen. Neither were easy chances, but perhaps a recognised striker might have done better.

Barcelona really need to show more in the second half. They are missing some key players tonight, but even accounting for that this has been a really disappointing display from the Catalan giants.

Messi, as ever, has looked like their brightest spark, but he has not got enough help from his teammates and Olympiacos will head into the second half optimistic of their chances of coming away with a famous result.

KICKOFF: Barcelona get us back underway for the second half.

Barcelona have begun the second half at an increased tempo, which is surely what Valverde must have told them during the break. It remains to be seen whether that enables them to cause the hosts more problems, though.

Busquets plays a defence-splitting pass through the middle which Messi almost latches on to, but it is just too far in front of him and races through to the keeper. That would have been the sort of incisive play which may be needed to break through this Olympiacos defence tonight.

Barcelona may be in stunning form, but some fans are not quite sold on Ernesto Valverde and performances like this will do nothing to win them over. This has been far short of what we have come to expect from this team.

Olympiacos break forward again, this time down the right flank, but they have so many players behind the ball that there is no-one up there in support and the eventual cross flies straight into the arms of the keeper.

Chance for Barcelona to break as Messi draws three defenders towards him before playing the ball out to Denis Suarez, but he turns down the chance to shoot and eventually the chance fizzles out. Poor decision from Suarez then.

UPDATE: Atletico Madrid have levelled things up against Qarabag through Thomas Partey, while PSG are now 3-0 ahead against Anderlecht, with former Barca winger Neymar and Layvin Kurzawa on the scoresheet.

YELLOW CARD! Engels picks up a retrospective yellow card for a late foul on Suarez.

Olympiacos' belief seems to be growing a little here. They win a free kick in a good crossing position on the left flank...

The delivery from Fortounis is a dangerous one, but Ter Stegen bats it away with an important one-handed interception.

The resulting corner is only cleared as far as Figueiras, but his first-time volley from 25 yards flies well over the crossbar.

BARCELONA SUB: Valverde has seen enough here and makes his second change of the night as Ivan Rakitic replaces Paulinho.

CHANCE! Huge chance for Barcelona to break the deadlock! Olympiacos try to play out from the back, but Barca win the ball back and Messi is immediately in action. He gives the ball to Suarez, but the striker's touch is poor and he has to cut back on himself. He looks for the return pass to Messi, but the ball is a touch too deep and Messi can only put it wide of the target. That should have been a goal, and it isn't often Messi and Suarez don't punish teams from that position.

UPDATE: Chelsea's night is going from bad to worse - they now trail Roma 3-0 at the Stadio Olimpico through Diego Perotti.

Elsewhere, Qarabag have had a man sent off, while CSKA Moscow have levelled things up against Basel.

Barcelona knock the ball about amongst themselves, but that only makes the whistles from the home fans louder and louder. Relentless noise from the supporters.

Luis Suarez in particular has been really disappointing for Barcelona tonight. He has looked short on confidence, wasting some good chances in the process, and it looks as though he really needs a goal.

There is a truly horrendous sound being played in the stadium every time Barcelona have the ball. The fans themselves are whistling as loud as they can to try to put the visitors off, and now it sounds like a megaphone is being used to amplify some sort of high-pitched and relentless noise.

Suarez almost finds room to have a go for goal, but Botia sticks at it and manages to deny the striker. Less than 20 minutes remaining now.

UPDATE: Celtic could be on the verge of a famous result in Glasgow - they have just levelled things up against Bayern Munich.

OLYMPIACOS SUB: The hosts make a change as we head into the final 15 minutes as Guillaume Gillet replaces Odjidja.

BARCELONA SUB: Barca make a change of their own - their third and final one - as Denis Suarez is replaced by Andre Gomes.

YELLOW CARD! It hasn't taken long for Andre Gomes to go into the book. He is booked within a minute of his introduction.

OLYMPIACOS SUB: Another change for the home side sees Felipe Pardo replace Carcela-Gonzalez.

OFF THE BAR! Barcelona are close to breaking the deadlock as Suarez beats the offside trap to race through on goal, but his finish is indicative of his performance tonight. He hesitates and, while he still manages to lift the ball over the keeper and onto the top of the crossbar, you can't help but think an in-form Suarez would have finished that.

Brilliant defending from Botia to deny Suarez again, with the Barca striker's space immediately closed down as he was pulling the trigger.

UPDATE: The goals are flying in elsewhere now, including one in the group's other game as Juventus level things up against Sporting through Higuain.

Elsewhere, Layvin Kurzawa has scored a hat-trick to put PSG 5-0 up against Anderlecht, Manchester United now lead Benfica 2-0, Bayern Munich are 2-1 ahead against Celtic and CSKA Moscow lead Basel.

OLYMPIACOS SUB: A third and final change for the hosts sees Uros Djurdjevic replace Fortounis.

Barcelona have only failed to score in one of their last 47 Champions League group games, but they only have a few minutes to prevent that record being ended tonight. Olympiacos are on the verge of a huge result, but Barca have a free kick in a dangerous position...

SAVE! Messi again gets the free kick on target, but it is comfortable for the keeper to bat away once again.

There will be three minutes of added time at the end of this match.

SAVE! Messi almost rescues Barcelona again as he tries to curl a low one into the bottom corner, but Proto gets down well to turn it away. That could have been the moment!

Olympiacos hold on for a famous point at home to Barcelona, who were so out of sorts tonight that they can't have many complaints at coming away from this own with only a draw.

The visitors dominated possession from start to finish, but they were far short of their usual standards and didn't create as many chances as you would expect given how much of the ball they had. It is the first time they have dropped points in this season's Champions League, although they remain three points clear of Juventus at the top of Group D.

Right, that is all we have time for this evening!

Thank you very much for joining Sports Mole for tonight's match as Barcelona are held to a frustrating stalemate by Olympiacos in Athens. I will leave you with our match report, and be sure to stick around for reaction too. From me, though, it is goodbye for now!