It was much closer than manager Jurgen Klopp would have wanted, especially after taking a 12th-minute lead through Naby Keita.

But the CONCACAF Champions League winners proved tough opponents and when Rogelio Funes Mori, twin brother of former Everton defender Ramiro, equalised just two minutes later it became a slog for the much-changed Reds.

Liverpool started the match without Virgil Van Dijk for the first time in a major game this season – he has not played in the Carabao Cup – and it was the one area of the team Klopp could not afford to be weakened.

Illness ruled out the Holland captain, leaving the Reds boss with Joe Gomez as his only available central defender with two youngsters in Ki-Jana Hoever and Sepp Van Den Berg en route from England after playing at Aston Villa in a League Cup quarter-final which kicked off just 21 hours and 45 minutes before this one.

With Joel Matip, Dejan Lovren, Fabinho and Georginio Wijnaldum all injured it left Klopp no option but to deploy midfielder Jordan Henderson, and while his distribution came in handy it was an unnecessary disruption which Monterrey were able to capitalise on.

But having struck first through Keita's third goal in as many games – matching his tally from his first 41 for the club – Liverpool had little time to build on their lead as the unmarked Funes Mori swept home after Alisson Becker had parried Jesus Gallardo's shot.

But there was one man whom the majority of the crowd had come to see and he did not disappoint.

Every move by Salah, the most high-profile Arabic footballer playing in an Arabic country, was cheered and he turned on the style early on with the clever reverse-pass to lay on Keita's goal.

A backheel put in the overlapping James Milner, but the angle was narrow and too close to the keeper and Marcelo Barovero made the block, while Salah himself was denied on the edge by Nicolas Sanchez as the centre-back made a brilliant recovering tackle having initially lost possession.

But while Salah was dictating things at one end Monterrey were proving a threat at the other and twice Alisson had to push away angled drives from Dorlan Pabon, with the Monterrey captain's early second-half free-kick also having the Brazil international at full stretch.

Liverpool's usual intensity was lacking, maybe somewhat understandably having left behind a Premier League title challenge to fly over 3,000 miles to the Middle East to play on a pitch hosting its third match in 24 hours.

Monterrey, of course had travelled even further but with the benefit of having already played one match in Doha were no mugs, and looked capable of exploiting those deficiencies despite being dominated in possession.

Keita shot straight at the goalkeeper, Alex Oxlade-Chamberlain wide while Divock Origi had a goal correctly ruled out for offside as Klopp's side started to pick up the tempo.

The late introductions of Sadio Mane and Trent Alexander-Arnold gave Liverpool a more recognisable look but it was Firmino, who came off the bench with five minutes to go, who had the decisive say.

Salah did well to hold up the ball on the right of the area and when he dropped it back Alexander-Arnold fired in one of his trademark low crosses and the Brazilian did the rest.