When Didier Drogba returned to Chelsea, there was an audible sigh among Gooners, remembering the Ivorian's prolific form over the past decade against them.
Drogba has an astounding record of 15 goals in 15 games against Arsenal, and began to be a real threat even mentally for Arsene Wenger's side to deal with.
He this week however confirmed that he would miss the game, due to aggravating an ankle problem.
This has double benefit for the Gunners. While a 36-year-old Drogba isn't the threat he was, Chelsea won't be able to call on him off the bench to inspire the side and worry Arsenal.
It also means a more spent Diego Costa. Jose Mourinho wanted to rest the Spaniard in midweek against Sporting Lisbon, but instead he will be playing twice in a week, something the Chelsea boss has indicated already he is reticent to do.
Arsenal need any advantage they can get against a Chelsea side who thrashed them 6-0 at the Bridge last season and have 16 points from a possible 18 this campaign. This is at least one factor in their favour.