Wojciech Szczesny insists Arsenal can still turn their UEFA Champions League last 16 tie with AC Milan around, despite going down 4-0 in the first leg at the San Siro.
The Gunners fell behind to a stunning opener from Kevin-Prince Boateng in Milan on Wednesday night before a Robinho brace and a Zlatan Ibrahimovic penalty completed the rout.
Goalkeeper Szczesny knows Arsene Wenger's men have set themselves an uphill task in the second leg at Emirates Stadium but insists nothing is impossible.
And the Poland international is hoping for a good result at Sunderland in the FA Cup on Saturday to inspire confidence.
"It's going to be very hard, especially against AC Milan," he told Sky Sports. "They showed tonight how good they are. But it's not impossible.
"We're going to have to pick ourselves up, do our best in the next game against Sunderland and hopefully that will give us confidence to go into the second leg.
"We still believe we can turn it around but it's going to be very difficult."
Szczesny feels Arsenal were unlucky after Milan were awarded a penalty for Johan Djourou's adjudged foul on Ibrahimovic in the box.
"I think it's harsh. But it was given so we can't change it right now," he said. "The referee is the one that makes the decision."
Arsenal committed several defensive errors to allow Milan's goal rush and Szczesny admits they must improve in the second leg.
"It's hard to say because they only had five shots on goal. The quality of their finishes was unbelievable," he said.
"It's hard to say right now but I hope we can improve in the second leg."
Why have English clubs performed so poorly in the Champions League this season?
Squads have not improved
Rest of Europe has caught up
Players not good enough