After surprise defeats to Aston Villa and Crystal Palace in recent weeks, the Blues have recovered well, recording victories over Stoke City and Swansea City in their last two outings.
With four games to go, and a potential title decider at Anfield next weekend, Mourinho knows his side can ill-afford any more slip-ups if it is to claim a fourth Premier League crown.
Gus Poyet, meanwhile, returns to his former club hoping Sunderland can build on Wednesday's morale-boosting 2-2 draw at Manchester City.
The Uruguayan spent four years at Stamford Bridge from 1997 to 2001, and became a cult hero for his rampaging runs and goal-scoring exploits from midfield.
Sunderland did Jose Mourinho's Chelsea a huge favor in the title race by holding City at the Etihad Stadium midweek, with the Premier League's bottom club only denied a crucial three points two minutes from time when a Samir Nasri effort squirmed past keeper Vito Mannone.
Poyet was encouraged by his side's showing in Manchester, which halted a run of five straight defeats, and hopes it will give it a boost heading into this weekend.
"It was an excellent performance by us against City," he told reporters. "It's the sort of performance which is going to give us that word that I absolutely hate — which is 'confidence.'
"I don't like using that word that, but it is true. Given as well as we played against City, it will give us a bit of hope against Chelsea this weekend. I think now the players will believe they might get something."
Despite Wednesday's hard-earned draw, Sunderland remains rooted to the foot of the table, six points from safety with five games remaining, and will be without Phil Bardsley (suspended) and Ki Sung-Yueng (tendonitis) for the trip to West London.
Midfielder Liam Bridcutt was absent from the draw at the Etihad due to personal reasons, while Steven Fletcher (ankle) and Carlos Cuellar (knock) remain doubtful.
Chelsea, meanwhile, may be without Eden Hazard again after he was sidelined for the trip to Swansea following his withdrawal in the Champions League quarterfinal against Paris-Saint Germain with a calf problem.
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