1st half
United clearly needed a bit of time to get back into rhythm after the international break.
The defence were a bit asleep at the start of the match - at least, that's the only reasonable explanation Danny Welbeck found himself alone and unmarked when he scored the opener.
It didn't become much better for the Red Devils before the break while Brighton had opportunities to double the lead.
2nd half
After exchanging some strong words at half-time, United came on to dominate the game after the break.
It was nothing spectacular, but Brighton were smothered and could not do anything in the Red Devils' half: they managed precisely zero shot attempts and, as a result, their xG after the break was 0.0.
At the other end of the pitch, meanwhile, the pressure was mounting on Robert Sanchez who, in the end, was powerless against Marcus Rashford's precise shot and Mason Greenwood's unexpected header.
Overall, it was not the most spectacular performance but at least, United got the job done unlike some of the clubs who are already left far behind in the Premier League table.
Team rating: 6/10