The Arsenal manager believes the striker's confidence has been boosted by his goal against West Ham and admits his performances could have been due to fatigue.
The forward has scored just twice in his last eight games and was criticized for his displays during Arsenal's recent run of four Premier League games without a win.
The France international netted a well-taken equalizer in Tuesday's 3-1 win over West Ham which has put Arsenal one point ahead of fifth-placed Everton in the race for a Champions League place.
"It gives him credibility again for people who questioned his ability, so that is important."
Wenger admits Giroud's performances may have been the result of fatigue but believes the striker’s mental strength has helped him recover.
"He has done well. He has gone, like Mesut Ozil, through a more difficult period recently. It was a bit physical and mental as well with what happened to him," Wenger continued. "He is a strong lad, strong mentality, a strong, positive guy. He has a great mentality and that's what I think got him back. He has scored 20 goals, that is a great record, and he is working very hard for the team.
"For a while he played maybe too many games but he's a strong guy, he can cope with it. Up front it's difficult because every challenge he goes into is physical. He’s not a guy who moves away from people to get the ball. He's a guy who fights with people to get the ball. When he comes out of the game he has 50 fights behind him. That is more demanding than the guy who just runs away."
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