Arsenal boss Arsene Wenger admits his team has been over-confident at times this season.
The Gunners boss fears his team are becoming too cocky in Europe after reaching last season's final.
And he has made it clear he will not tolerate another half-hearted display from his stars in tomorrow's clash with Group G leaders CSKA Moscow.
Arsenal are now sweating on their place in the next round after losing 1-0 in Russia two weeks ago.
Wenger said: "I was very positive going to Moscow but as a team we were too confident of taking the points.
"We were warned by Porto that CSKA were a difficult side to beat.
"But we only came into the game after we had gone a goal down.
"Before that we were not giving 100 per cent in every tackle, we were not fighting for the ball enough. It was an arrogant way of not being urgent.
"It was as though we were thinking, 'Don't worry, we will do it'.
"We were just not sharp enough to create something against a team who defended with eight players around their box."
maybe but they soon realize they should not be 2 cocky if they want to challange chelsea for the epl title