The loss ended Arsenal’s eight-game unbeaten run in the league which had seen Wenger’s side leapfrog Tottenham Hotspur into third place.
But Spurs’ 3-1 victory over Swansea City on Sunday moved Harry Redknapp’s side level on points with the Gunners, while Chelsea and Newcastle United are five points behind the north London pair.
Arsenal welcome title-chasing Manchester City to The Emirates next Sunday – and Wenger has called on his side to make a big improvement on their defensive display.
“We have to take the distance with that and put things into perspective,” Wenger told Arsenal’s website.
“We have to go back to basics; that means to win football games and win your fights first.
“We have to play like we do. It is disappointing to lose a big run in the way that we did it here. At the end of the day the result does not lie.
“The focus was missing a little bit and the way we conceded the goals [was disappointing]. I felt that we lacked something, I do not deny that.
“We have been consistent recently and you have to give credit to the team. But in this game we were poor and we were not good enough.”
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