Johan Djourou says Arsenal cannot take Chelsea\'s fatigue factor for granted when the London rivals meet at Emirates Stadium on Saturday. Both clubs are involved a four-way battle for two Champions League places with Arsène Wenger\'s side currently in third, seven points clear of sixth-place Chelsea having played a game more. Roberto di Matteo\'s side face Barcelona on Wednesday - their fifth game in 14 days - but Djourou does not expect them to feel the effects of fixture congestion at the Emirates. \"They still want to have Champions League football next season as well so we know it is going to be a tough game,\" he told Arsenal Player. \"Obviously they have a lot of fixtures, the two Barcelona games are [either side of Saturday\'s derby] but we don\'t really concentrate on that. We have to be focused on our game and be focused on what we do best. \"We need to play football the way we did against Manchester City and Wolves, that is the sort of situation we have to get back into. We have to show that again. Unfortunately it wasn\'t the case against Wigan but we have to be sure it is there on Saturday.\" Arsenal\'s own route into Europe was hampered by Monday night\'s defeat to Wigan but Djourou believes his team are still in the driving seat. \"Of course we are and we would rather be in that situation,\" he said. \"It was a disappointing result, we know that, and now we have to dig in and just go forward because Saturday is around the corner and we have to make sure we are ready for that.\"