Arsenal boss Arsene Wenger has blamed his defensive department after defeat to Bayern Munich on Wednesday night.
The Gunners needed to avoid defeat to keep their Champions League hopes alive but suffered a humiliating 5-1 defeat at the hands of the German champions at the Allianz Arena.
And the Frenchman says Arsenal have only a "small" change to reach the Last 16.
"You have to give credit to Bayern first for their quality and on top of that we made things quite easy for them," Wenger told reporters.
"It was a bad defensive performance and we were extremely poor defensively. We were not at the races. The funny thing is that when we went forward we created good chances. We had a chance to score early but with a defensive performance like that, you go nowhere.
"My memory of 19 years is not too accurate if I'm supposed to tell you our worst defensive performance. It's certainly not going to remain in my memory for anything positive.
"There is still a chance to qualify. Olympiakos have to lose here, we have to beat Zagreb and then we will see when we play Olympiakos away.
"It's a small chance but it is a real one. We have to realise with that kind of performance that we had today that our chances are minimal.
"No matter what percentage we have, we have to dig in for the chance to qualify.
"We now have to focus on the Premier League on Sunday and bounce back with a different performance because we are in a good position in the league. It's important that we realise what we did today and we know that."