Wenger denied that the defence had been shaky in their 4-3 win over Leicester last week, but agreed that what turned out to be the decisive goal at Stoke should have been prevented.
“Last week we conceded two goals on corners and they only had three shots on goal, so I don’t believe we defended so badly,” said Wenger after Saturday’s loss. “On set-pieces, yes.
“But here I say we could look at ourselves and, on the goal we conceded, we were 100 per cent guilty.
“We are very frustrated because we lost a game that we should have won and that’s terrible to swallow.
“We had plenty of chances and on top of that, not only did we not finish, but we gave them an easy goal to score, just after half-time.
“We knew at half-time it was very important to keep our defensive focus in this kind of game, (then) we came out and didn’t defend properly. That’s where we are not forgivable today.”
And Wenger implied that the defence will be focused on this week ahead of a tricky trip to Liverpool next Sunday.
“At the end of the day I believe when you are not concentrating on the way you want to play, you pay for it at that level,” he said.
“In the Premier League you do not get away with defending like we did on the goal.
“We have to realise as well, that if we want to transform the energy we put into the game as well like that, you have to defend properly, every single minute.
“But it is vital to not only see the negative side of it and to respond very quickly in the next game.”