Brighton is definitely not an easy opponent and they are clearly stronger than Southampton, especially since Brighton has the advantage of playing at home.
Brighton are not at home against United tomorrow, the game is at Old Trafford, so Manchester United play at home.
Now it remains to be seen whether Man United can return to winning ways and maintain their consistency, or whether they will get another disappointing result.
If Manchester United play the same way they played against Southampton, they will definitely lose to Brighton. I know United won against Southampton, but there were not the better side and they were very lucky to get three goals in the last minutes, of course we know Brighton wouldn't make mistakes like Southampton.