The Hammers are enjoying a fantastic season and will go above Manchester City into the Champions League places on 52 points - level with the Gunners - if they come away with three points from Stamford Bridge.
No matter what temporary boss Guus Hiddink says, Chelsea's season was all but ended when they crashed out of the FA Cup to Everton last time out.
That game will be remembered for a fantastic free-kick from Hammers hero Dimitri Payet, who has been one of the signings of the season.
And Chelsea, already without suspended star striker Diego Costa, should beware the Frenchman on Saturday after he looked red hot in training ahead of the crunch game.
Video from West Ham's Chadwell Heath training ground was posted out on the club's official Instagram account showing just what Payet is capable of as he twisted teammate Manuel Lanzini and coach Edin Terzic inside out.
It was a case of now you see him, now you don't as Payet went one way and completely sold a dummy to his equally skillful midfield partner before showing up the former Borussia Dortmund coach.
Screams can be heard from fellow players at Payet's audacious skill and the Hammers will be hoping its their fans screaming on Saturday as they aim to do the double over the Blues following a 2-1 win at Upton Park in the reverse fixture.