City reached the last four thanks to a late strike from substitute Sergio Aguero, but Wenger highlighted the performance of 18-year-old Oxlade-Chamberlain.
He said: "Chamberlain the whole night looked like he could deliver something special and he has shown already he has moved forward. He has improved a lot."
There may now be pressure from the Arsenal supporters to see Oxlade-Chamberlain on a more frequent basis but Wenger believes he has adopted the correct policy with the 18-year-old former Southampton player.
"The experience shows that it is good sometimes to be positive and patient," Wenger said.
"I was very patient with him until now and it is important sometimes to hold them back a little bit and keep them on the training ground."
Oxlade-Chamberlain had long been linked with a move to Emirates Stadium and made the switch from Southampton for a reported £12million over the summer.
Despite the fee, Wenger has resisted the temptation to plunge the youngster into the side on a regular basis, and he claims the youngster is developing all the time.
Wenger said: "(I was surprised) by the consistency of his game. You pushed him off the ball too easily two months ago.
"His strength and endurance is now there and that is important at the top level of course."