Ralf Rangnick’s men slumped to a 4-0 defeat at the Amex Stadium, putting on a sorry showing in their penultimate game of the season.
Brighton were the better team throughout and managed three goals in 11 second-half minutes to put the game to bed after taking a one-goal lead in at the break.
United have now given West Ham United the opportunity to move into sixth place should the Hammers win their two games in hand.
League position aside, this was one of the Red Devils’ worst performance of the season, as performances continue to struggle under Rangnick.
And Match of the Day pundit Shearer slammed United for their display, dubbing them an ‘embarassment’ for their latest efforts.
“They were shambolic, Manchester United, they were an embarrassment. And if he hasn't already, Ralf Rangnick should get his players in tomorrow and show them the performance from Brighton.
“Because this is what committed footballers do for their club, their fans, for their teammates and their managers.
“They work hard, they are prepared to put a shift in, they are organised and they are committed. It should be a given, but it's not at Manchester United.
“They should watch this, because these Brighton players today showed what they should do for their fans.
“They were magnificent, and some of the football they played was fantastic. They [United] are totally lost, but what are they doing on the training ground?
“You have to work on things, and that's what Brighton do. United were an embarrassment to their football club today.”