Chelsea capitalised on Manchester United’s second-half collapse to secure a third consecutive defeat for the visitors, piling further pressure on manager Michael Carrick.
United are now without a victory in nine consecutive matches across all competitions, their worst run since October-November 1988.
The defeat, their fourth in the Premier League this season, leaves them 16th on the table, just one point above the relegation zone, with Carrick’s position becoming increasingly uncertain.
Despite an encouraging first-half display, United struggled after the break, allowing Morgan Rogers to break through their defence and chip the ball past the goalkeeper five minutes into the second half.
Chelsea extended their advantage in the 64th minute when Cole Palmer converted a penalty after VAR officials spotted Lisandro Martinez striking Wesley Fofana in the face with his arm.
Martinez received a second yellow card and was sent off, leaving United with 10 men and making their comeback increasingly difficult.
Chelsea almost added a third through Estevao, who was making his first Premier League start of the season under Xabi Alonso, but his effort was ruled out for offside.
United had shown promise before the break, with Matheus Cunha having a close-range header disallowed following a VAR review for offside.
Bruno Fernandes also missed a good opportunity, while Amad Diallo failed to convert two promising chances against Chelsea goalkeeper Mike Penders.
However, United failed to maintain their first-half intensity, allowing Chelsea to take control after the interval.
The hosts, who had received some boos from their supporters at half-time, responded with an improved performance, as Rogers’ opener and Palmer’s penalty put them firmly in command.
Chelsea created further opportunities to increase their lead, with Estevao coming close and substitute Valentin Barco missing a clear late chance.
United nearly pulled one back in stoppage time when Bryan Mbeumo struck the crossbar, but the effort proved insufficient to change the outcome.
While Chelsea climbed to fourth place in the Premier League standings, United could end the weekend in the relegation zone, adding to the pressure surrounding Carrick.
