Arsenal boss Arsene Wenger admits he was wrong to play Wojciech Szczesny in victory over Southampton.

Szczesny is out of the Champions League opener with Montpellier due to an ankle injury.

Wenger accepts it would have perhaps been better to rest the Pole again after he suffered the new problem during the warm-up.

"He says not, but of course we had a question in our minds before the game: do we change him or not? We decided to leave him on - maybe it was a mistake," Wenger said.