Arsenal manager Arsene Wenger claimed their display in the 3-1 defeat against Bayern Munich was "our worst peformance in the Champions League".
Kolo Toure's late goal gives the Gunners hope for the second leg, but Wenger said: "The only positive is that we are still in the tie.
"The players are really down in the dressing-room. I feel we really turned in a bad performance.
"At 3-0 we faced a real struggle, but 3-1 at least gives us a chance."
Goalscorer Toure was also at fault for two goals, and Wenger said: "We need to help Toure rebuild his confidence as he is low at the moment."
Wenger also tried to stay upbeat himself, adding: "But there is enough time for crying. I could cry - maybe it would be easier - but life goes on.
"In this job, you have good and bad nights. This was a bad night - but I still have confidence in the quality of my players, as well as their spirit and desire."
But Wenger's Bayern counterpart Felix Magath was in no mood to celebrate either.
He said: "I am far from happy despite the win. My players failed to try and score a fourth to kill the tie and then conceded the late goal.
"Arsenal are fully capable of scoring several goals against us on their own turf."
Arsenal keeper Jens Lehmann, whose personal rivalry with Bayern goalkeeper Oliver Kahn was not helped by the result, said: "Do I blame myself for the third goal? As a goalkeeper, I always blame myself.
"I just know the goals were very easy against us. In my time here, we have never conceded three easy goals like that - but sometimes it happens.
"It would have been impossible to go through at 3-0 - but with the goal we have chances. Everything is now possible."