Arsenal's boss confirmed the Poland international will start against Partizan Belgrade in one of European football's least forgiving arenas after Almunia was ruled out with an elbow injury.
Not-so-great expectations: Lukasz Fabianski returns to the Champions League for the first time since his clanger at Porto last season
It transpired that Almunia hurt his right arm on Saturday during the clash with Peter Odemwingie that led to West Brom's first-half penalty, before an uncharacteristic second-half collapse saw Arsenal slide to a surprise 3-2 defeat.
Wenger shrugged off suggestions that this was in any way a 'diplomatic' knock, with club officials confirming that Arsenal's stand-in skipper had indeed suffered a genuine injury.
Looking back: Arsenal Manager Arsene Wenger insists he still has complete faith in Manuel Almunia
It means that Fabianski will be afforded the opportunity to atone for some high-profile blunders when he steps onto the Stadium Partizan pitch.
It was at Porto last season where the 25-year-old's nervousness and inexperience shone through as he was largely responsible for the two goals that presented Wenger's side with a far more difficult return leg in north London than otherwise would have awaited them.
Mistakes against Wigan Athletic and Blackburn followed before the campaign was over, while his error last week at Tottenham has contributed to the questions about Fabianski's capabilities.
With both of Wenger's shot-stoppers looking decidedly incapable of living up to that tag, it makes his decision not to pursue Fulham's Mark Schwarzer more aggressively seem puzzling, especially in the light of the whopping £56million pre-tax profit the Gunners declared recently.
Confirming that Fabianski would start, while at the same insisting Almunia had not been dropped, Wenger said: 'No, the keeper is always the easy target, an easy scapegoat.
'Even if people think he (Almunia) made a mistake on the second goal (against West Brom), we made a few before that as a team. We win together and we lose together.
'But Almunia won't play because he is injured. He did his right elbow in making the penalty. We checked him at half-time and he had some pain but said he could go on, so I decided to play him on.
'I would have taken him out on Saturday if he had said, "I'm feeling it". Sometimes when you are playing you only feel it after you stop.
'I have no concerns about Fabianski. Only you in the media have concerns. He made mistakes against Porto, but he can show that he has learnt from that.'
It all means that Arsenal, so buoyant following a hitherto blemish-free opening to their campaign, arrived in the Serbian capital last night short of a captain, shorn of their first-choice keeper and with confidence too at a low ebb.
Wenger made light of the captaincy issue - the armband is likely to be tossed to Tomas Rosicky - but admitted that some of the assuredness of their early-season form had been hit by the setback at the weekend.
'The mood was very low because we were all disappointed,' Wenger said. 'It is still low. I've not yet found a measurement of the lowness of a football team.
'It is the first game we have lost. And as a manager I must take perspective. What we are doing is outstanding. But we were very disappointed.
'Physically, what we did was tremendous. The statistics were the highest this season in terms of the sprints we made and the distance ran. You cannot say we lacked effort. We lacked sharpness, maybe, but the quality of work was there.
'I will tell the players to continue to play the way we want and to believe in themselves.'
The reigning Serbian champions, who are unbeaten this season, willbe eyeing up Arsenal with a sense of relish as they look to claim theirfirst ever scalp in the group stages of the competition.
Wenger,meanwhile, appears to have been shaken just days before one of thebiggest dates on the club's calendar against Chelsea at StamfordBridge.
Enlarge In what is likely to be a vastly changed line-up, bearing in mind that the reigning Barclays Premier League champions await this weekend, Wenger admitted that he would have no concerns about the temperament of Jack Wilshire, if the 18-year-old is picked tonight.
'I would not be afraid to play him,' he said. 'It is a possibility he will play. I rested him on Saturday. It was just a question of having a breather. He is 18 and has played every single game recently.'
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