Chelsea manager Enzo Maresca thought Manchester United defender Lisandro Martinez was fortunate not to be sent off for his late challenge on Cole Palmer.
Ruud van Nistelrooy oversaw a comfortable victory over Leicester City in the Carabao Cup in his first game as interim boss but couldn't make it two wins in two games against Chelsea.
Although Chelsea arrived at Old Trafford in good form - they have lost just twice in the league this season - it was United who drew first blood in the second half through Bruno Fernandes.
Rasmus Hojlund was brought down by Robert Sanchez and won a penalty with 20 minutes remaining, which Fernandes slotted into the bottom left corner. ALSO READ: United player ratings from Chelsea fixture ALSO READ: United vs Chelsea as it happened United needed to see out the final exchanges of the contest to claim a much-needed league victory but conceded just four minutes later after an excellent strike from Moises Caicedo.
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