The Gunners must overcome a 1-0 deficit to reach the Champions League final in Rome.
Almunia said: “1-0 in this stadium is not that bad a result because there are not that many teams who play here and go away with a clean sheet.
“We expected them to start with a high tempo but in the second half we showed that if Arsenal can keep the ball, then we can beat them.
“We have to be more or less happy and look forward to the second leg at the Emirates.
“It is our last chance to do something this year, so we will try to put all of the pressure on Manchester United and the fans will help as well.”
