The German playmaker was unable to convert from the spot early in the Gunners' eventual 2-0 loss to Bayern Munich at the Emirates Stadium on February 19 which Wenger feels affected his summer signing.
However, ahead of Tuesday night's return leg at the Allianz Arena, Wenger suggests Ozil is over the miss and in a good mindframe to try and overcome the reigning European champions.
"I think it affected him mentally too much, the penalty he missed against Bayern. It was not only physical, it was mental," said Wenger.
"He had the feeling he let the team down at a very important moment of the game, that affected his performance very much.
"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."
Wenger added: "Ozil is hugely respected in Germany, but we live in a society where the period of time is very short between the boos to the applause. We have to live with that."
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