Chris Hughton's Brighton ran out fully deserved winners as lacklustre United suffered an embarrasing defeat in our first away game of the season. It was Albion's second successive win over the Reds, having beaten United to secure their Premier League survival in the corresponding fixture back in May.
Glenn Murray and Shane Duffy scored twice in as many minutes, and although Romelu Lukaku halved the deficit, a Pascal Gross penalty re-established Albion's two-goal lead. Paul Pogba's spot-kick with virtually the last kick of the game gave the scoreline a flattering look that the Reds did not deserve. A chastening day was made worse by the performances of Jose Mourinho's £61m centre-back pairing of Eric Bailly and Victor Lindelof, at fault for all three of the Seagulls goals during an inept and woeful showing in keeping with the performance of the team as a collective.
United had actually had the first opening of the game inside ten minutes when Pogba collected the ball, drove forwards, and picked out Lukaku with a wonderfully weighted pass, but the Belgian - on his first start of the campaign - put the ball narrowly wide.
Despite that early chance, the south coast side began to seize the upper hand as Anthony Knockaert dragged a shot wide on 20 minutes. Five minutes later, Albion moved in front when local lad Solly March picked out Murray and he touched the ball home beyond the wrong-footed David de Gea.
With United still reeling, the AMEX erupted again two minutes later when Bailly's sliced clearance went out for a corner, the Reds failed to clear the resultant flag-kick and Duffy capitalised from close range.
In a frantic first half, United were thrown a lifeline through Lukaku, who untidily headed home from a Luke Shaw cross to give us hope.
However, that hope was soon extinguished as the Reds fell 3-1 behind, and again proved architects of their own downfall as Bailly's reckless lunge scythed down Gross, and he dusted himself down, made no mistake from the spot and restored the Seagulls two-goal advantage at the interval.
Pogba flicked a header wide and substitute defender Leon Balogun cleared well under pressure from Lukaku, but Brighton were comfortable as United failed to make inroads despite having more of the ball. Murray went close on the counter-attack, and Mat Ryan saved superbly at the other end as he tipped wide to keep out Pogba's dipping effort from distance.
The Albion keeper proved powerless prevent the World Cup winner's injury-time penalty - after Marouane Fellaini had been brought down - but it proved too little, too late. Brighton were worthy winners, United were terrible and we go again with the visit of Tottenham next Monday.
Overall team performance: 2/10
United Faithful Man of the Match: No one. They were all as bad as each other.