Chelsea made the brighter start, with Estevao causing problems down the right flank. The Brazilian thought he had opened the scoring after 15 minutes when he followed up Pedro Neto's effort, but his goal was ruled out for offside.
United gradually found their way into the game, with Amad Diallo proving particularly dangerous. Bruno Fernandes wasted a promising opportunity by firing over the crossbar, while Mike Penders denied Diallo twice. Matheus Cunha also had a goal disallowed for offside, leaving both sides frustrated at the interval.
Chelsea broke the deadlock shortly after half-time through Morgan Rogers. After Romeo Lavia won possession in midfield, the England international drove towards the United defence before producing a clever finish, lifting the ball over goalkeeper Senne Lammens.
United's hopes of recovering suffered another major blow when Lisandro Martinez was sent off. The Argentine defender received a second yellow card after barging into Wesley Fofana during a Chelsea corner, with VAR confirming a penalty.
Cole Palmer converted from the spot to make it 2-0, despite Lammens getting a hand to his effort. The goal effectively ended United's hopes of rescuing a result, with Chelsea taking control against their 10-man opponents.
Estevao thought he had added a third after being set up by Palmer, but the goal was ruled out for offside. Lammens also produced another save to deny the Brazilian, while Bryan Mbeumo struck the crossbar in stoppage time for United.
The victory was an important one for Chelsea, who have now recorded only their third Premier League win in seven matches.
Following their 2-0 victory over Manchester United, Chelsea move up to 4th place in the Premier League table with 16 points from 9 matches. Manchester United remain in 16th place with 7 points from 9 matches.
Tottenham continued their resurgence under Roberto De Zerbi with a 2-0 Premier League victory over Crystal Palace, extending their winning streak to three matches and climbing into the top half of the table.
Manchester City were defeated 1-0 by Brighton and Hove Albion in their Premier League fixture on Saturday evening to hand them their second loss of the season.
Youri Tielemans has thrown his support behind Michael Carrick, insisting Manchester United need stability rather than another managerial change as they attempt to turn around their poor start to the season.
Arsenal manager Mikel Arteta has backed Kai Havertz to make an impact against Liverpool, insisting the forward remains an important figure in his plans despite his recent goalscoring form.
