Brighton is part of the new wave and have only lost one game so far (to another up-and-coming club, West Ham). They have done it with attacking football. ManU is always expected to do well, especially at home. So far they have lost two and only beat minnows, Fulham and Wolves by one goal each.
Usually ManU has a stout defense at home but will be missing Shaw on the back line and Varane is questionable. But ManU is 6th in the EPL in saves so lots of shots are getting through. ManU is still without Mount and now will also be missing Antony as well for their attack which was already middle of the pack in shots on target, shot creation and attacking penalty area touches. Sancho has been out of favor as well but may have worked his way back for this game.
Brighton is in sharp contrast to this as they lead the EPL in goals for, shots on target, shot creation and attacking penalty area touches. Brighton is one of the most creative attacking sides in the EPL and they will have a chance to exploit a hurting and vulnerable ManU defence.
Add to this that Brighton has won 3 and tied one of their last 4 head-to-head matches and you have a clincher for choosing Brighton to take the points offered and win the game.