Arsenal midfielder Mikel Arteta has said that his side's defending of set pieces during their past two Premier League matches has not been good enough.
The Gunners were held to a 1-1 draw at Manchester City last weekend, after Joleon Lescott had put the English champions ahead by heading home David Silva's first-half corner.
Arsene Wenger's men were then beaten 2-1 at home by Chelsea yesterday, with both goals coming from Juan Mata free kicks.
"We have conceded three goals from three set pieces in the last two games that cost us points and it is not good enough," said Arteta.
"I don't think it is something to do with the defence, it is to do with an individual set-up in the game, which is a free kick or a corner or whatever, and we haven't defended the ball well enough and we conceded three goals in those two games.
"You cannot blame one player, you have to clear the lines so quickly and you cannot allow runners like that in the box, and it was the same sort of ball for both goals.
"It hurts when you lose points at home against teams like that and you feel you haven't deserved to lose. It is frustrating, but I think it was our own fault because we didn't defend those set pieces."
Arsenal are currently seventh in the Premier League table, having taken nine points from their opening six matches.