Manchester United 2 Brighton & Hove Albion 0
Albion lost at Old Trafford after being on top for most of the first half. The catalyst was the sending off of Lewis Dunk after 54 minutes.
The Seagulls had a series of good first-half chances, with Jakub Moder forcing a great save from David De Gea and Yves Bissouma firing wide when almost being too precise.
The game turned early in the second half as Cristiano Ronaldo burst clear and fired past Robert Sanchez to put United 1-0 up.
Soon after, Lewis Dunk was adjudged to have hauled down Anthony Elanga.
The referee Peter Bankes initially awarded a free kick and gave Dunk a yellow card.
But after the intervention of VAR, and even though Adam Webster was in a covering position, Bankes changed his mind and Dunk saw red.
Albion, however, continued to press United. Moder fired an excellent shot that hit the crossbar and Danny Welbeck, on as a substitute for Pascal Gross, had a couple of good chances, one in particular late on which he stabbed wide when he should have done better.
After a succession of late United corners and some more penetrating wing play from another Albion substitute, Tariq Lamptey, it was eventually Bruno Fernandes who broke clear and, like last season, finished Albion off with a 97th minute goal.
The Seagulls take on bottom of the table Burnley on Saturday (19 February) at the Amex.