West Ham went into last weekend’s game against Southampton on the back of three straight defeats, but David Moyes’ side produced a stunning first-half performance to seal a crucial 3-0 win.
Meanwhile, Chelsea suffered a 3-1 defeat against rivals Spurs last weekend, and Hammers goalkeeper Joe Hart believes that they could leave west London with some points in the bag providing they back up their performance from against the Saints.
He told the club’s official website: “We’ve got to concentrate on us on Sunday. If we perform to the best of our ability and give a good account of themselves, you never know.
“Chelsea will play as they do and prepare as they prepare, and they’re a top-quality team who won the league last year and a couple of results aren’t going to affect them too badly.
“As I said, I think we’ve just got to look after us and give a good account of ourselves.”