The former Bayer Leverkusen man had to be patient, making his debut in the Europa League win over Vorskla Poltava, but has performed well since taking the gloves following Cech’s injury and kept a clean sheet in the 1-0 Europa League win away to Sporting Lisbon on Thursday night.

Leno, 26, appears much more comfortable with playing out from the back – a style encouraged by Emery ever since he took over at the Emirates Stadium.

Cech, on the other hand, made a number of slip ups attempting to adapt to the new demands – but that does not mean he will automatically miss out on a recall at Selhurst Park.

“For Sunday Petr Cech is okay and we must decide whether to play him in the first XI or not,” Emery said.

“We have very big confidence in all the goalkeepers and I am happy with the way they work with the coaches.

“It’s a big decision but it’s also a positive one because they are both (capable of) a good performance.

“Now we are very happy with Leno and before Petr Cech had the injury he was also giving very good performances.”

The Gunners make the short trip to south London looking for a 12th consecutive win in all competitions.

Emery has not tasted defeat since August 18 and has called on his whole squad, whether in the team or not, to keep the momentum going.

“It’s very important (we are) all feeling together in every match,” he said.

“It’s important the players have commitment and good behaviour in every training and every match, whether they are starting in the first XI or on the bench.

“The team is getting better in each game, we are finding every moment the balance for the attacking and defensive moments.

“I want to continue improving the individual quality and performances because I think it’s better for the team if each player is improving things.

“I’m not surprised (to win 11 games in a row) because I believe in this team.

“But I know it isn’t easy to win each match.

“We need continue thinking only about the next match. Crystal Palace away was a very difficult match in Arsenal’s history but we are going to prepare for the best performance for us.”

As well as having a dilemma over who will start in goal, Emery will be sweating over the fitness of both Nacho Monreal and Sead Kolasinac.

The two left-backs missed Thursday’s Europa League win at Sporting Lisbon with hamstring complaints as Granit Xhaka dropped in to fill the gap.

The pair will be assessed ahead of the clash with the Eagles, with Xhaka again likely to deputise if needed.

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