Sczesny has taken advantage of an injury to Lukasz Fabianski to regain the number one jersey, despite being dropped in March following a series of indifferent performances.
Wenger believes that Szczesny needs strong competition to add drive and edge to his performances and has credited the Polish shot-stopper for responding with a strong work ethic.
He told the club's official website: "It (the competition) is very good for him. You know him as well. I must give him credit because in this competition [from Fabianski], he responded very well, worked hard and when he came back, he was sharper when I left him out.
"They always came back stronger. He does that well. He's in good form now."