The attacker struck the winner against QPR on Saturday.
Wenger said: "Many people say he can play through the middle. Yes he can, but it's difficult to find flank players who can score goals.
"I try to combine the two, put a player through the middle who can score, knowing that I have another one as well.
"He's more mature, more ready for a fight, resists better to the duels and the timing of his runs is fantastic. But what he has improved a lot is his finishing.
"He's a great finisher now and you favour him every time he's in front of goal."