Barely five minutes of the second half had elapsed when David Moyes must have realised it was not going to be his day. With West Ham trailing to a penalty from Alexis Mac Allister – his first Premier League goal since winning the World Cup with Argentina – the visitors came close to stealing possession in the Brighton penalty area as they pressed for an equaliser. In a matter of seconds, the ball was down the other end after a succession of quick passes allowed Brighton to break the press, with Joël Veltman touching home the resulting corner from Mac Allister’s flick on to double his side’s lead. Further goals from Kaoru Mitoma and the substitute Danny Welbeck meant Brighton made it 12 matches unbeaten against West Ham in the top flight to seriously strengthen their hopes of European qualification for next season. For Moyes, who had to endure choruses of “You don’t know what you’re doing” from sections of the away support, it was a deeply concerning defeat – their heaviest since August 2019 – that leaves West Ham teetering on the brink of the relegation zone once more. “We let ourselves down,” he said. “That’s one of the worst results and worst performances since I’ve been here. I totally understand the fans’ reaction. They have been watching a team that has been doing really well over the last few seasons so it’s hard for them to watch that.” Roberto De Zerbi entrusted assistants Andrea Maldera and Enrico Venturelli – fluent in Italian, English, Russian and Spanish – with filling his shoes on the touchline as he served a one-match ban. The Italian had shrugged off the importance of being forced to watch on from the stands because “the players know very well what they have to do” and Brighton certainly did not let him down with a committed performance that showed the chasm in class between the two sides. “The second half was fantastic, but I still think we can improve,” said De Zerbi, whose side are now three points behind fifth-placed Newcastle with a game in hand. “I think we can achieve our target because we are a very focused group.” Despite being knocked out of the FA Cup by Manchester United in midweek, West Ham had arrived on the south coast in a hopeful mood after their crushing win over Nottingham Forest last week. Not since a 6-0 thrashing at Upton Park in the Championship have they beaten Brighton, however, in a sequence that dates back to 2012. Their chances of ending that looked slim from the moment Jarrod Bowen clumsily brought down Mitoma inside the area after he had been picked out by Solly March with a perfect crossfield pass. Mac Allister comfortably sent Alphonse Areola the wrong way from the spot for his eighth goal of a season he will never forget. Bowen had a great chance to make amends for conceding the penalty when he raced through on goal after some hesitancy in Brighton’s defence, but his effort was easily repelled by Jason Steele, who was making the second Premier League appearance of his career at the age of 32 and had an otherwise untroubled afternoon. Moyes had named six outfield players on the bench and opted to replace the ineffective Saïd Benrahma with Pablo Fornals at the start of the second half. But it was Mac Allister who continued to pull the strings as one effort flew just over the bar before a quick break downfield ended with his back heel being diverted behind for a corner. Then, to Moyes’s clear dismay, somehow it was the diminutive No 10 who jumped highest to flick on Pascal Gross’s corner for Veltman to apply the simplest of finishes with his chest. Only a smart save from Areola stopped Evan Ferguson from adding a third immediately as West Ham’s players appeared to momentarily lose their heads. Tomas Soucek and Declan Rice were shown yellow cards for very late challenges on Moisés Caicedo and Mac Allister respectively, while Bowen was also cautioned after a dive in the area that had West Ham’s bench up on their feet to protest. Mitoma then made it three by touching home Gross’s cross and it was only thanks to some excellent late saves from Areola that things did not become even worse before Welbeck finally compounded West Ham’s misery with a fourth.