United raced into an early two-goal lead inside the first 20 minutes with Pereira on target.
Before Propper bundled the ball into his own net following Fred’s delivery, while Brighton failed to provide any real goalscoring threat in the opening period aside from Connolly’s headed effort.
Brighton then started the second half well, and it looked as though it could be a difficult afternoon for United when Dunk nodded home to pull one back,
But Rashford then restored the two-goal cushion minutes later with his powerful effort.
There were two further chances for Rashford, while Williams also went close towards the end, but it remained 3-1 to the hosts as they returned to winning ways in the Premier League.
Ole Gunnar Solskjaer will surely be happy with side securing all important 3 points at home.