Giroud ended a run of four games without a goal by scoring his side's second at the Emirates Stadium, and Wenger was keen to pay tribute to the striker for his ability to recover from missing a good chance in the first half.
"It was a perfect first touch. He has gone through a difficult period, as you know," the Gunners boss told reporters. "I think it affected his game for a while, and his confidence.
"At half-time he came in, he was very, very down because he missed a great chance in the first half. But he responded very well in the second, because he is a mentally strong guy."
Arsenal's victory saw them return to fourth in the Premier League.