London: Per Mertesacker accepted Arsenal undid all of their recent good defensive work by not being "switched on" in allowing Tottenham to come from behind to win the north London derby 2-1 at White Hart Lane.


Per Mertesacker 

"We found a way recently to prepare ourselves on crosses better defensively (and also) on set-pieces, but we did not switch on quickly enough and were not up for proper defending, so that was worse than in recent weeks," Mertesacker said on Arsenal Player.