The Emirates Stadium side blew the chance to open up an eight-point lead over North London rivals Tottenham Hotspur and surprise package Newcastle United by losing at home to lowly Wigan Athletic on Monday.
And they now head into a crucial home fixture against fellow London juggernauts Chelsea knowing that defeat to Roberto Di Matteo's men will put qualification for next season's Champions League in serious jeopardy.
"They [Chelsea] still want to have Champions League football next season as well so we know it is going to be a tough game," Djourou told the club's official website.
"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."
Wigan’s surprising victory was only Arsenal’s second defeat in 10 games, a run that had seen them open up a five-point gap over North London rivals Tottenham.
However, the defeat means Spurs and Newcastle can close the gap to two points if they win their games in hand.
Djourou insisted that Arsenal are only focused on looking forward, adding: "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."
Saturday's game against Chelsea will be vital in the race for fourth place. Victory for Arsenal will all but secure their ticket into the Champions League, with games against Stoke City, Norwich City and West Bromwich Albion to come in their remaining fixtures.
By Dean Mears
