"To be honest, I can't remember before and afterwards. It's a bit of a blur. But I felt I'd let my friends down, the team-mates, the management and everyone in the ground because it was just ludicrous."
Arsenal were heading for a victory when Freddie Ljungberg gave them the lead following Prutton's sending off moments before half-time, but the dismissal of Robin Van Persie allowed Southampton back in the game.
Having been booked for catching Rory Delap with an arm in the first half, the Dutchman received a second yellow for a late tackle on Graeme Le Saux. Saints took advantage, with Peter Crouch earning a 1-1 draw.
Wenger was furious with Van Persie but Ashley Cole insists his team-mate should not be blamed for
Arsenal's failure to win. He said: "Robin hasn't let anyone down. I've done it before and I hope nobody blamed me. It's something that can happen in the spur of the moment." But Wenger took a different view. He said: "Robin has a lot to learn. He should not have done it and he's intelligent enough to know that as well."
Van Persie's indiscipline leaves Wenger with a striker dilemma ahead of tomorrow's FA Cup fifth-round replay at Sheffield United.
Pires, who suffered ankle ligament damage in the tackle that led to a red card for Prutton, is definitely out of tomorrow's clash and faces a race to be fit for the Champions League return leg with Bayern Munich next week.