Danny Welbeck returned to haunt United with a deserved opening goal for the Seagulls in the first half at Old Trafford on Sunday.

Second-placed United raised their game after the break, though, and the fit-again Rashford marked his return with a well taken equaliser.

Greenwood, also passed fit after recovering from an injury, headed home the winner seven minutes from time to stun the Seagulls in the absence of Anthony Martial, who could be out for the season with a knee problem.

Victory for the Red Devils strengthened their grip on second place, 14 point behind leaders Manchester City with a game in hand, while Brighton are six points above the drop zone.