The 20-year-old had only made three League Cup appearances before last night's big clash at Old Trafford, but was called upon to start a massive Premier League game.
Szczesny didn't let anybody down though and certainly wasn't at fault for the United winner, which came four minutes before the break from Park Ji-Sung.
Wenger was pleased with the Pole, saying: "The goalkeeper performed well. He was a bit nervous in his kicking but he didn't make any mistakes with his hands.
"It was a big game. But in this job you do not look at the size of the game. You look at the quality of the player."