Arsene Wenger insists Arsenal can fight back from a 3-1 deficit against Bayern Munich on Wednesday and reach the Champions League quarter-finals.
The absence of goalkeeper Wojciech Szczesny, Jack Wilshere and Bacary Sanga has also added to Arsenal's task.
But Wenger says: "It is difficult we know that, but it is not impossible.
"The only way to make it possible is to have a real go - that's what we'll do. Turning up expecting to go out would be absolutely unacceptable for us."
As well as the first-leg scoreline and a depleted squad, Bayern Munich's formidable home record will also challenge Arsenal's ambitions.
The German side have not conceded three goals at home since losing to Inter Milan in the Champions League two years ago. In this season's Bundesliga campaign, Bayern have only let in 10 goals in 25 matches.
But Wenger argued: "We have big experience in the Champions League and in Europe we have basically won everywhere and that means we have the right to believe.
"I am convinced that if this team can find a big game you will see a completely different animal.
"This season we have fought to find that in the big games and we have another opportunity [on Wednesday]. I hope the team takes this chance.
"I have a great respect for this team and its attitude and they have not been rewarded yet.
"It is important for the end to our season that we do it."
Arsenal lie fifth in the Premier League and out of the Champions League qualifying places.
Wenger's side were also dumped out of the FA Cup by Championship side Blackburn.
Arsenal are still searching for their first trophy since winning the FA Cup in 2005.
Although Wenger has faced criticism this season, it is understood that the Frenchman's position is not under threat even if his Champions League campaign ends on Wednesday and the club fail to qualify for next season's competition.