Guus Hiddink’s side will host the top-chasing Hammers at Stamford Bridge fresh from their FA Cup exit last weekend after a 2-0 defeat by Everton.
West Ham were denied a place in the last four after Anthony Martial’s equaliser forced a FA Cup quarter-final replay at Upton Park next month.
Slaven Bilic’s side are two points behind fourth-placed Manchester City after their impressive run of results in the Premier League.
Former Aston Villa and Everton forward Gray is confident that the Hammers can secure a score draw with the defending champions this weekend.
“I love the look of this London derby. West Ham have a lot to play for because people seem to be forgetting about them in the race for fourth,” Gray told Paddy Power’s blog.
“I open my papers and I see people talking about Man City, Man United, Liverpool and even Chelsea, but no one is mentioning Slaven Bilic’s Hammers.
“Chelsea are in flying form but remember: West Ham have already beaten Man City, Liverpool and Arsenal away from home. Who says they can’t take another scalp?”
West Ham are hoping to qualify for the Champions League for the first time in the club’s history.
The Hammers were 2-1 winners against Chelsea at Upton Park earlier in the Premier League campaign when Jose Mourinho was still in charge.
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