The Blues have only taken one point from their last two league games and had played a game more than their top-four rivals, but the poor form of those behind them means that they remain one point clear of Arsenal and three above Sunday's hosts.
United have been on a particularly bad run, and Chelsea know that if they can pile more misery on Ole Gunnar Solskjaer's side this weekend then they would be just two wins away from securing Champions League football next season.
Here, Sports Mole looks at how Maurizio Sarri could set his side up for the contest.
Chelsea's draw at home to Burnley on Monday was bad enough without the injuries that came with it - not to mention Sarri being sent from the touchline and the ugly scenes that greeted the final whistle.
N'Golo Kante was forced off at half time in that match due to a rib injury, although it was confirmed after the game that it is not a serious problem and he could be fit in time for Sunday's clash.
The more devastating blow came to Callum Hudson-Odoi, whose ruptured Achilles tendon will keep him sidelined throughout the summer and likely into the start of next season too.
Pedro appears the most likely to take the youngster's place in the starting XI, although Willian is also expected to be available to join Gonzalo Higuain and Eden Hazard in the front three, with the latter having been a controversial exclusion from the PFA Team of the Year.
Ruben Loftus-Cheek, Ross Barkley and Mateo Kovacic will do battle for the third midfield spot if Kante is passed fit, and there could be injury boosts at the back with Antonio Rudiger given a "strong chance" of recovering from a knee injury in time to feature.
Marcos Alonso is also expected to return to fitness for this match, although he has fallen out of favour during the second half of the season and Emerson Palmieri could keep his place at left-back even if the Spaniard is available.