Rasmus Hojlund made it four Premier League goals in as many games and Alejandro Garnacho scored twice as Manchester United recorded their biggest home league win of the season to move back into the top six against West Ham at Old Trafford.
Hojlund celebrated his 21st birthday in perfect fashion, providing the smart 23rd-minute finish that set the hosts on their way to victory.
Garnacho's deflected effort doubled their advantage less than a minute after West Ham full-back Emerson wasted a glorious chance to equalise. The Argentine added another near the end after Scott McTominay seized possession inside the West Ham half.
Remarkably, it was the first time Manchester United had won three successive games since October and only the second time they had managed it all season.
The Red Devils have scored 11 goals in three games in the past week, having netted just 10 times in their previous 10 matches.
The victory came at a cost though as combative defender Lisandro Martinez, in only the fourth game of his comeback from foot surgery, seemed to injure his knee in a second-half tussle with Vladimir Coufal and, although he tried to continue, he had to be replaced shortly afterwards.
It was a case of what might have been for a West Ham side who drop to seventh. Emerson failed to take another chance after Garnacho's goal and Diogo Dalot slid in to make a brilliant block shortly afterwards when Jarrod Bowen ran free onto a long ball that dropped over the head of Harry Maguire.
Hojlund on fire for Red Devils
Prospective new chief executive Omar Berrada was not at the first home game since his impending appointment was announced but Ineos was represented by Sir Dave Brailsford, whose views are evidently going to be pivotal in determining United's direction once Sir Jim Ratcliffe's 25% purchase is confirmed by the Premier League at some point this month.
If boss Erik ten Hag cannot deliver a return to the Champions League, he must at least be able to point to a bright future in order to secure his job. Hojlund could be a key part of that.
For most of this season, questions have been asked of United's recruitment and why they decided against trying to sign Harry Kane and opted to spend £72m on Denmark striker Hojlund instead.
By Christmas Day, Hojlund was still to score a league goal. Now he has four in four games after breaking his duck against Aston Villa on 26 December. There was a mixture of dexterity and brutality involved in his latest effort.
After Casemiro had snapped into a tackle, Hojlund moved smartly to his right to create room to shoot, then slammed a low shot into the bottom corner from the edge of the area. He is now in double figures for the season in all competitions.
At 19, Garnacho is even younger than Hojlund. While it would be asking a lot for the teenager to match the career of Cristiano Ronaldo, there is a similarity with the Portuguese superstar's formative years in the way Garnacho produces moments of sublime skill, followed by the wrong decision.
However, he benefited from a slice of good fortune when he cut in off the right wing and saw his shot deflected in off Nayef Aguerd. The home fans will hope the celebration shot of Garnacho, Hojlund and 18-year-old Kobbie Mainoo sat together on an advertising board in front of the Stretford End is a sign of the future Ten Hag needs to deliver.
Mainoo had gone off by the time Garnacho scored his second. His replacement McTominay drove forward with purpose to create it as Manchester United went back into the top six for the first time in almost two months, even though they are still eight points behind fourth-placed Aston Villa.
West Ham pay for Emerson miss
Having come out on top in their previous two games against Manchester United, West Ham were aiming for a third successive triumph, something they had not previously achieved since the mid-1970s.
They could count themselves unfortunate to be behind at the break, by which time they had attempted 13 shots at the home goal and Onana had somehow managed to keep out a Tomas Soucek effort that deflected off Aguerd and was heading for the corner.
Emerson should have levelled after robbing Maguire in the Manchester United half. Yet, after charging into the penalty area with purpose, he then seemed to get in a muddle as he was trying to position himself to shoot. He had already narrowed his own angle before he stabbed his left foot at the ball, which sailed harmlessly wide, much to Onana's relief.
Manager David Moyes' additional worry will concern goalkeeper Alphonse Areola, who was caught in the face by Kurt Zouma in a first-half collision. Areola made it through to half-time but was replaced by Lukasz Fabianski at the break.
Manchester United will mark 66 years since the Munich air disaster on 6 February.
As it was the nearest home game to that date, the customary service was held outside Old Trafford two hours before kick-off.
Ten Hag and Moyes laid wreaths before kick-off, with the respective sides coming out to the 'Flowers of Manchester' anthem, which pays tribute to the eight players, including England stars Duncan Edwards, Tommy Taylor and Roger Byrne, who were among the 23 passengers who died when the club's flight back from a European Cup quarter-final in Belgrade crashed on take-off after a refuelling stop.
It is the first anniversary to pass since the death of Sir Bobby Charlton, who was the last surviving United player on that flight.