Germany midfielder Ozil has failed to score for Arsenal since early-December, a run of eight games that has prompted speculation that the former Real Madrid playmaker could be relegated to the substitutes' bench in the Allianz Arena.

But despite confirming that David Ospina will replace Petr Cech in goal, thereby continuing his run of playing in every one of Arsenal's Champions League games this season, Wenger stopped short of issuing a similar vote of confidence for Ozil.

"It's not the best moment to give you the team," Wenger told a news conference. "I will pick the team tomorrow morning. But we play in Germany and you will see that Ozil is highly focused to have a good performance tomorrow."

Arsenal are bidding to progress beyond the Champions League round of 16 for the first time since the 2009-10 campaign, having fallen at this stage in each of the last six seasons. And defender Laurent Koscielny insists that Wenger's players are ready to prove their unity and commitment against Carlo Ancelotti's team.

"We are united, the dressing-room plays well together," Koscielny said. "You have good and bad moments during a season, but that is when you see how you respond. "We had bad moments against Watford and Chelsea, but it was very important to come back with a win against Hull on Saturday.

"We know we are capable to win here, though, because we have done it in the past. We know the first game here is very important because we have the second game at home.

"But the first game is really important and we must have a good result tomorrow."