Petr Cech believes that Arsenal can overturn their 2-0 first-leg deficit by Barcelona and still qualify for the Champions League quarter-finals - if they take their chances at Camp Nou.
The Gunners' hopes of reaching the last eight were dealt a massive blow on Tuesday as a second-half brace from Lionel Messi helped Barca effectively put one foot in the next round.
As a result, Cech, who helped Chelsea to Champions League glory in 2012, says that his Arsenal team-mates can turn the tie around if they rediscover their killer instinct in Catalonia.
The goalkeeper told Arsenal's official website: "We had some opportunities and we should have scored. I think that would have made them a bit more defensive.
"Another blow is the second goal where they got a penalty to make it 2-0. It is a difficult deficit to overcome but 2-0 is not 5-0 and we have 90 minutes with a chance."
Arsene Wenger's side travel to Barcelona for the return leg on March 16, where failure to progress would mark the club's elimination at the last-16 stage for a fifth straight year.
The Londoners were losing quarter-finalists to the Catalans in 2010, and again in the second round a year later.