Chamakh was recalled for the win.
Wenger told arsenal.com: "I think he worked very hard. He is running after a goal at the moment. I felt there were two or three occasions in the first half where he was nearly there on crosses and just didn't get in front of Shawcross. I am pleased with his effort. I think he knows in his mind that at the moment Van Persie is untouchable.
"Because we play with two wingers it is very difficult to play with two strikers because you are too open in the middle of the park. So unless I change the system it will be him or Van Persie. It is difficult. But he will get confidence by playing games and scoring goals like all strikers."