The Gunners boss says the penalty miss in the first leg had a big mental effect on the German but insists he has moved on and is ready to show his quality.
The North Londoners travel to Germany trailing 2-0 from the first leg but will take confidence from the knowledge they won by the same score at the Allianz Arena last season.
Ozil missed a penalty in the first leg at the Emirates, in a disappointing display, but Wenger says he is over the incident and is getting back to his best after scoring in Saturday's 4-1 FA Cup win over Everton.
"Psychologically sometimes the wound is like a physical one. You can talk and talk and talk, but it takes time. You just have to leave it to time. I think he is over it. He has a good opportunity to show on Tuesday night how good he is.
"The way the players celebrated was certainly important to him, and to the team as well. He was absolutely outstanding from the first to the last minute."
Wenger also acknowledged that the Germany international is still adapting to life in the Premier League following his big-money summer move from Real Madrid.
"I would like him to find the right balance between being a provider and finisher," he added. "At the moment the balance is a bit detrimental to the finishing. His strong side is providing.
"But he is pacy, much quicker than people think he is, and with that technical quality and that pace, if he gets into the right areas and with the service he has, he can score goals. He wants to score more goals, I am convinced of that. The physical part of the game is certainly something he has to adapt to. First you have to convince yourself mentally that you have to do it.
"Then to adapt physically. Against Everton, he looked to me to have a really complete performance on both sides, defensive and offensive."