Former Red Danny Welbeck has put the Seagulls into the lead at the break at the so-called Theatre of Dreams.
The 20th minute goal followed great play, initially from Seagulls keeper Jason Steele, the a super cross from Simon Adringa.
Tariq Lamptey picked up a yellow card after just four minutes and later Jan Paul van Hecke was also nooked.
Welbeck, again, and the industrious Kaoru Mitoma have also gone close to extending Albion’s lead.
United have had the ball in the net but the effort, from Rasmus Hojlund on his full debut, was ruled out by VAR as the ball was out of play from Marcus Rashford’s cross.
