Steve Bould says that Arsenal have suffered since the international break.
Arsenal have played poorly in defeats to Norwich and now Schalke in recent days.
"It is frustrating, of course. We've not played anywhere like we can," said the Arsenal assistant coach, who took charge of the team for last night's match with Schalke.
"We lack a bit of confidence for whatever reason. A lack of chances is not what we are accustomed to and we need to correct that. I don't know why that is. Coming off the international break we haven't performed."