Gallas received a neutral reception from Arsenal fans when he first touched the ball.
He was inches from a Robin van Persie free-kick and also had a strike ruled out for offside.
In the second half he blocked a Van Persie shot that appeared to be heading for goal.
"I believe his focus was great," Wenger said. "He wanted to do well and you could see he was completely committed in the game.
"Overall, I feel he did well. The crowd responded well. Somewhere, they acknowledge that he was a committed captain and I was very happy that the crowd reacted in this way to him."