Mason Greenwood was on target while Bruno Fernandes grabbed a brace for the Red Devils.
Following an action-packed opening half, Manchester United took a two-goal lead in at the break.
The visitors have been in control for much of the first half, and got their breakthrough following an incisive piece of play from Greenwood who coolly slotted in the opener after 16 minutes.
The Red Devils then doubled their lead 13 minutes later when Fernandes found the bottom right corner with a perfectly-placed strike from the edge of the area.
Bruno Fernandes then doubled his tally of the night just 5 minutes into second half as Greenwood clipped a dangerous cross in towards the back of opposition post. Fernandes arrives and volleys the delivery beyond Ryan from the middle of the box.
The win send Solskjaer’s team back up to fifth in the table as they look to host Bournemouth in their next outing to continue their unbeaten start.
While Brighton will be seeking to bounce back next time out in the league when they travel to face Norwich City.