Arsenal goalkeeper Wojciech Szczesny has claimed that his side were "childish" during the collapse against Fulham on Monday.
The Gunners led 1-0 but conceded two late goals to crash to a 2-1 defeat at Craven Cottage.
The keeper also believes that tiredness was a factor but refused to blame the defeat on the congested fixture list.
Szczesny said: "There was probably some tired legs but I think probably we should have kept the concentration and focus and we would have been fine.
"But it was a very childish performance in the end from us."
Arsene Wenger's side are now fifth in the Premier League.
