But now the Pole is looking to put that mistake behind him and focus upon getting a result in Basle tomorrow.
He said: "When you are a goal-keeper you can't allow yourself to dwell on these things," said Dudek. "Every goal-keeper in the game makes a mistake sometimes. When it happens you often see it highlighted a lot more than if it's an outfield player because it usually leads to a goal.
"I still feel good about my game and my performances and I won't allow myself to worry about it. It's something I want to put behind me and bounce back in the right way by doing everything I can to help us in Basle."
I came out to catch the long ball and I just dropped it. The referee seemed to check with the linesman but it was my fault and my mis-take. I had the ball in my hand but it was a difficult situation with so many players in there and that's why I dropped it.
"It was a typical goal-keeper mistake but I can't remember the last time I made one like that.
"I feel very sorry for the lads and the fans because we had worked hard in the game and if we had kept it at 0-0 and come away with a draw away from home it would have been a good result.
"By the time we conceded that goal it was too late for us to come back with an equaliser because there were just a few minutes to go. Now we are determined to come back strongly against Basle