Ralf Rangnick apologised to Manchester United’s supporters after their “unacceptable” defeat which ensured the club will finish with their lowest Premier League points tally. United have been accused of being on the beach during their dismal season and Rangnick’s hapless team, who are in danger of missing out on Europa League qualification, were all at sea with Brighton rampant on the south coast. Rangnick said: “To start with it’s important to apologise to our supporters. They came all the way from Manchester to Brighton. We were just not good enough from start to finish. The performance was very poor. “It was a humiliating defeat today. Even more so for Manchester United. It was the second highest defeat in my career. It wasn’t just that we lost 4-0, but it was the way we played. It was unacceptable.” Graham Potter’s side raced out of the blocks and Moisés Caicedo’s early strike put Brighton in command. Second-half goals from Marc Cucurella, Pascal Gross and the exceptional Leandro Trossard, in the space of 11 minutes, dished out a new low for United’s team of misfits as they slumped to a fifth successive away defeat. Brighton had not won at home since Boxing Day but it felt like Christmas arrived early for the home fans after this euphoric victory. Erik ten Hag is focused on winning the title at Ajax before he can start his new job at Old Trafford, but when the incoming manager watches a rerun of this shambolic showing he could be forgiven for questioning his decision to take up the challenge. A monumental rebuilding job lies ahead and Brighton ruthlessly exposed all the failings in United’s broken team. Potter, who described it as the best atmosphere during his tenure in front of a record Brighton crowd, said: “We have had to suffer a little bit at home, in terms of giving our supporters more happy memories. I think we made up for it today. “It was a great performance and a fantastic result. As much as it’s about wins and league tables, it’s about creating memories and moments we can share with people and today was special.” The hosts made a bright start but Danny Welbeck was unable to guide his header from Trossard’s cross on target. Trossard looked in the mood to trouble United and was carrying a threat for Brighton down the wing. United had lost their previous four away matches and there was a tentativeness to their play which underlined their recent struggles. Their sluggish start was summed up by Cristiano Ronaldo wastefully sending a short-range pass out of play to the delight of the home fans. Brighton were much sharper to the ball and their positivity was rewarded with the breakthrough after 15 minutes. Gross’s shot was charged down and the ball fell to Caicedo, who fired a low strike from the edge of the area beyond the despairing dive of David de Gea, for his first goal for the club. It was no more than Brighton deserved. In response, Bruno Fernandes ambitiously attempted a volley from the edge of the area but his miscued effort careered harmlessly out of play. Nemanja Matic was next in on the act but the midfielder’s tame effort was also well off target. United were struggling to deal with the influential Trossard and Welbeck blasted a volley over the crossbar from a free-kick with Brighton continuing to dominate. They threatened again, after Scott McTominay carelessly conceded possession inside his own half, but Trossard dragged his shot wide of the far post. Ronaldo had the chance to finally test Robert Sánchez before the break, from a free-kick in a dangerous position, but frustratingly blasted his strike over the bar. Brighton came close to adding a second goal just before half-time, after Raphaël Varane miscontrolled Sánchez’s long clearance down the pitch, but Welbeck was unable to direct his volley on target. It would have topped off an excellent first-half performance from the hosts against their fragile opponents and a sign of the dominance to come. Rangnick was rightly unimpressed with the first 45 minutes and opted to introduce Fred and Edinson Cavani in place of Matic and Anthony Elanga in a double change at half-time. But within three minutes of the restart United fell further behind. Trossard teed up Cucurella and the Spanish defender blasted the ball into the roof of the net from close range. The Amex Stadium was rocking and United were on extremely shaky ground. It took 55 minutes for United’s first shot on target but Juan Mata’s volley floated straight into the arms of Sánchez. Brighton compounded United’s misery with their third goal after Trossard played in Gross and the midfielder calmly sidefooted the ball past De Gea. It got even worse for the visitors when Diogo Dalot’s clearance was chested into the net by Trossard for Brighton’s fourth goal. It was checked by VAR for a possible handball but there was absolutely no respite for United. Alexis Mac Allister was denied a fifth Brighton goal with his shot deflected on to the post by Dalot. United’s despair was summed up when Cavani’s goal was ruled offside. He had tapped the ball home after the substitute Harry Maguire’s header was parried by Sanchez. Welbeck almost added another goal late on – his shot drifted past the post – but this was a five-star performance from Brighton and another hugely painful blow for this sorry United team.