Manchester United manager Erik ten Hag says "you can see potential" in his team after they brushed aside West Ham to move back into the Premier League top six.
Rasmus Hojlund made it four Premier League goals in as many games and Alejandro Garnacho scored twice as the Red Devils recorded a comfortable victory.
For Ten Hag, there was some satisfaction in their biggest home league win of the season on the day he was finally able to select from an almost full-strength squad.
Lisandro Martinez's worrying knee injury may rob Ten Hag of that position for an extended period but, after Hojlund marked his 21st birthday by opening the scoring and fellow youngster Garnacho added another two in the second half, the Dutchman was in bullish mood.
"I have seen all your pieces," he said, addressing journalists in his post-match news conference. "You didn't believe me.
"In the summer we bought players for the future and I have to analyse in a clinical and calm way.
"I am not telling you we are where we want but you see potential. But you can only work on the potential when a team is available.
"Now danger is coming from Licha Martinez, so I hope we don't go back. I hope we can keep them all fit. We can achieve a lot because in this Premier League everyone is killing everyone.".
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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.
It was a case of what might have been for a West Ham side who drop to seventh.
The home side's second came a minute after Emerson should have equalised and the Brazilian failed to take another chance after Garnacho's goal. Diogo Dalot slid in to make a brilliant block when Jarrod Bowen ran free onto a long ball that dropped over the head of Harry Maguire before Garnacho's second ensured West Ham would end up empty-handed.
After scoring 10 goals in their previous 10 games, Manchester United have now managed 11 in a week, starting with their FA Cup fourth round success at Newport.
Hojlund on fire for Red Devils
On the day Manchester United remembered the victims of the Munich air disaster, there was something fitting about the picture of Garnacho, Hojlund and Kobbie Mainoo sat on an advertising board in front of the Stretford End following their second goal.
Munich will always be synonymous with Matt Busby's youth policy on which the club's DNA is built.
For Ten Hag it is doubly important.
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 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.
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, who they visit next weekend.
"It was our plan [to play youngsters] before the season because we saw the potential but, of course, they need of games and they need experience," said Ten Hag.
"They have the right attitude and when you have the attitude to improve every day, I am convinced they can achieve high levels but they need experienced players who have achieved everything to help them and put them in the right positions.
"We have a front line that is a threat for every opponent and they enjoy to play football. The three youngsters celebrating together [was good]."
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.
Once Dalot had denied Bowen, there was no way back for West Ham, who suffered their first league defeat since the five-goal hammering at Fulham on 10 December.
Ironically, Moyes felt his side had played better on this occasion than they had in beating Manchester United in December.
He delivered good news on goalkeeper Alphonse Areola, who Moyes said had been replaced "as a precaution" at the break after he had been caught in the face by Kurt Zouma in a first-half collision.
Moyes also offered hope playmaker Lucas Paqueta soon return from a calf injury he suffered at the stat of January "in a week or two".
Munich remembered
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.
Player of the match
HøjlundRasmus Højlund
with an average of 7.51
Manchester United
Squad number11Player nameHøjlund
Squad number17Player nameGarnacho
Squad number37Player nameMainoo
Squad number39Player nameMcTominay
Squad number6Player nameLi Martínez
Squad number23Player nameShaw
Squad number18Player nameCasemiro
Squad number19Player nameVarane
Squad number20Player nameDiogo Dalot
Squad number8Player nameBruno Fernandes
Squad number2Player nameLindelöf
Squad number5Player nameMaguire
Squad number10Player nameRashford
Squad number24Player nameOnana
Squad number21Player nameAntony
West Ham United
Squad number14Player nameKudus
Squad number2Player nameJohnson
Squad number20Player nameBowen
Squad number19Player nameÁlvarez
Squad number7Player nameWard-Prowse
Squad number23Player nameAreola
Squad number28Player nameSoucek
Squad number33Player nameEmerson
Squad number5Player nameCoufal
Squad number27Player nameAguerd
Squad number4Player nameZouma
Squad number17Player nameCornet
Squad number1Player nameFabianski
Squad number11Player namePhillips
Line-ups
Man Utd
Formation 4-2-3-1
- 24Onana
- 20Dalot
- 5Maguire
- 6Li MartínezSubstituted forVaraneat 71'minutes
- 23ShawSubstituted forLindelöfat 88'minutes
- 37MainooSubstituted forMcTominayat 64'minutes
- 18Casemiro
- 17Garnacho
- 8Bruno Fernandes
- 10Rashford
- 11HøjlundSubstituted forAntonyat 88'minutes
Substitutes
- 1Bayindir
- 2Lindelöf
- 4S Amrabat
- 14Eriksen
- 16Diallo
- 19Varane
- 21Antony
- 39McTominay
- 62Forson
West Ham
Formation 4-2-3-1
- 23AreolaSubstituted forFabianskiat 45'minutes
- 5CoufalSubstituted forPhillipsat 72'minutes
- 4Zouma
- 27Aguerd
- 33Emerson
- 19Álvarez
- 28SoucekBooked at 37minsSubstituted forCornetat 72'minutes
- 2Johnson
- 7Ward-Prowse
- 14Kudus
- 20Bowen
Substitutes
- 1Fabianski
- 3Cresswell
- 11Phillips
- 15Mavropanos
- 17Cornet
- 18Ings
- 21Ogbonna
- 45Mubama
- 57Scarles
Referee:Andy Madley
Attendance:73,612
Live Text
Match ends, Manchester United 3, West Ham United 0.
Second Half ends, Manchester United 3, West Ham United 0.
Corner, West Ham United. Conceded by Harry Maguire.
Attempt blocked. Mohammed Kudus (West Ham United) left footed shot from the centre of the box is blocked. Assisted by Edson Álvarez.
Attempt missed. Mohammed Kudus (West Ham United) left footed shot from outside the box is close, but misses to the right. Assisted by Maxwel Cornet.
Attempt missed. Scott McTominay (Manchester United) right footed shot from outside the box is close, but misses to the left. Assisted by Marcus Rashford.
Foul by Ben Johnson (West Ham United).
Alejandro Garnacho (Manchester United) wins a free kick on the left wing.
Mohammed Kudus (West Ham United) wins a free kick in the defensive half.
Foul by Victor Lindelöf (Manchester United).
Substitution, Manchester United. Antony replaces Rasmus Højlund.
Substitution, Manchester United. Victor Lindelöf replaces Luke Shaw.
Attempt missed. Edson Álvarez (West Ham United) right footed shot from outside the box is just a bit too high. Assisted by Maxwel Cornet.
Goal! Manchester United 3, West Ham United 0. Alejandro Garnacho (Manchester United) right footed shot from the centre of the box to the centre of the goal. Assisted by Scott McTominay following a fast break.
Corner, Manchester United. Conceded by Kurt Zouma.
Corner, Manchester United. Conceded by Kurt Zouma.
Offside, Manchester United. Rasmus Højlund is caught offside.
Attempt missed. Kalvin Phillips (West Ham United) right footed shot from outside the box is too high.
Maxwel Cornet (West Ham United) wins a free kick on the left wing.
Foul by Diogo Dalot (Manchester United).