The Blues have struggled against West Brom and Newcastle recently and risk losing pace at the top of the table, while the Hammers recorded a 3-1 win in this fixture last season.Chelsea goes in search of its first win in three Premier League matches when it faces London rival West Ham at Upton Park on Saturday.
Jose Mourinho's side needed a controversial last-gasp penalty from Eden Hazard to draw 2-2 against West Brom before the international break. That came after a 2-0 defeat at Newcastle the previous weekend, and the Blues can ill afford to drop more points against Sam Allardyce's strugglers.
Chelsea lost 3-1 at Upton Park in December last year despite Juan Mata giving it an early lead, but that represents the only defeat in its last 15 meetings with West Ham.
Mourinho will be hoping that striker Fernando Torres is available to return after a leg injury kept him out of the last two games. If the Spain international is fit, he will vie for a starting berth with Samuel Eto'o. Midfielder Marco van Ginkel is a long-term absentee with a knee injury.
Ashley Cole is also a doubt after aggravating a rib injury during England's defeat to Germany on Tuesday, while Mata and David Luiz will also be hoping for a recall at the end of a week that marks a year since Roberto Di Matteo was sacked.
West Ham, meanwhile, is without a win in its last four Premier League games and sits level on points with third-bottom Fulham. Allardyce's side has only scored one goal in its last three top-flight matches and has been playing without a recognized striker in recent weeks in the continued absence of club-record signing Andy Carroll.
And the former Blackburn manager knows his team will have to be at its best if it is to get the better of Chelsea this time around.
"Anything less than top form for all of our players would make life difficult for us. We will have to produce the end product because chance creation will be harder," he said.
Allardyce is hopeful James Collins and Joey O'Brien (both hamstring) will be available for selection, but fellow defender Razvan Rat (hamstring) is a doubt.