Casemiro has scored four Premier League goals this season and set United on their way with the opener
Manchester United booked their Champions League place with a game to spare thanks to a comfortable win over a dismal Chelsea side at Old Trafford.
Casemiro headed the hosts in front, with Anthony Martial sweeping in Jadon Sancho's pass from close range to double their advantage.
Bruno Fernandes added United's third from the penalty spot after being fouled by Wesley Fofana.
And another Fofana error saw Marcus Rashford score a fourth before Joao Felix's late consolation for the Blues, who suffered their eighth defeat in 10 games under Frank Lampard and their 16th overall in a desperate campaign.
The result meant United consigned old rivals Liverpool to Europa League football next season.
It was not all good news for the home side though as Brazilian winger Antony was taken off on a stretcher in tears after suffering a lower leg injury in an innocuous challenge with Trevoh Chalobah - with the FA Cup final against Manchester City less than two weeks away.
For Chelsea, their sorry season - their worst in almost two decades - cannot come to an end quickly enough, although their fans have at least retained their sense of humour as they sang "we've scored a goal" as they celebrated Felix's effort.
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Easy night but work ahead for United
United manager Erik ten Hag made it clear in his programme notes that he wanted the Champions League place made secure immediately rather than let the situation drag on to create a tense finale against Fulham at the weekend.
It never looked likely they would fail to get the point they needed once Casemiro had been allowed to meet Christian Eriksen's free-kick unchallenged in a crowded penalty area to give the hosts a sixth-minute lead.
The Brazilian midfielder was the key component of a glorious second for the hosts, when he played a chipped, no-look pass beyond the Chelsea defence that allowed Sancho to present Martial with a tap-in.
Fernandes took the spot-kick himself after he had been fouled in the box 17 minutes from time, having also hit the bar and had another penalty claim turned down.
Nothing encapsulated the hapless nature of Chelsea's season more than United's fourth as somehow, in taking their own goal kick, the visitors presented the ball to Fernandes, who squared for Rashford to finish at the second attempt after Kepa Arrizabalaga had kept out his initial effort.
At that point, United were heading for their biggest win of the season and Chelsea their worst defeat.
Felix's effort changed that but the hosts were still the better team.
With the EFL Cup already won this has arguably been a successful season at Old Trafford no matter what the outcome of the FA Cup final.
However, given the knowledge that defeat to Manchester City at Wembley would leave their rivals two-thirds of the way towards winning a Treble only United have previously achieved, there is still a lot of work ahead of Ten Hag's side before the end of the season.
Lampard and Chelsea's misery continues
In the moments between Martial's goal and the half-time whistle, the TV cameras panned to Lampard, who sat on the bench, in silence, with his arms crossed.
What must have seemed like a free hit when he was asked to take over from Graham Potter until the end of the season at the beginning of last month has instead cast a major question mark over his future job prospects.
Eight defeats from 10 games, with little sign of even the semblance of a solution to the conundrum about how to mould a team out of the, theoretically, talented squad at his disposal.
At Old Trafford, Lampard named Chelsea's youngest-ever Premier League line-up.
He was rewarded with an excellent performance from 18-year-old full-back Lewis Hall, who had been wanted for England Under-20 World Cup duty in Argentina.
Hall delivered two superb crosses into the United box. Mykhaylo Mudryk failed to connect with the first. Kai Havertz headed the second wide from a central position when completely unmarked. In the second-half, Hall decided to go on his own, only for David de Gea to beat away his thunderous drive.
A precise Enzo Fernandez through ball set up Conor Gallagher but the England man was equally profligate as he dragged his shot wide of the far post.
Chelsea are heading for their worst league finish since 1994 and the end of the campaign, and the arrival of Mauricio Pochettino, cannot come quickly enough.
If there is any crumb of comfort for the Chelsea fans who continued to support their team despite their present state, it comes from the knowledge that 12 months ago United were similarly shambolic, their own interim manager Ralf Rangnick having failed to restore the club's fortunes following the sacking of Ole Gunnar Solskjaer.
Player of the match
with an average of 8.61
- Man UtdManchester UnitedManchester UnitedChelseaChelseaChelsea
Manchester UnitedAvgSquad number18Player nameCasemiroAverage rating
Squad number10Player nameRashfordAverage rating
Squad number29Player nameWan-BissakaAverage rating
Squad number2Player nameLindelöfAverage rating
Squad number19Player nameVaraneAverage rating
Squad number49Player nameGarnachoAverage rating
Squad number8Player nameBruno FernandesAverage rating
Squad number14Player nameEriksenAverage rating
Squad number1Player namede GeaAverage rating
Squad number25Player nameSanchoAverage rating
Squad number23Player nameShawAverage rating
Squad number12Player nameMalaciaAverage rating
Squad number17Player nameFredAverage rating
Squad number9Player nameMartialAverage rating
Squad number39Player nameMcTominayAverage rating
Squad number21Player nameAntonyAverage rating
ChelseaAvgSquad number11Player nameJoão FélixAverage rating
Squad number67Player nameHallAverage rating
Squad number1Player nameArrizabalagaAverage rating
Squad number5Player nameFernándezAverage rating
Squad number23Player nameGallagherAverage rating
Squad number28Player nameAzpilicuetaAverage rating
Squad number31Player nameMaduekeAverage rating
Squad number30Player nameChukwuemekaAverage rating
Squad number12Player nameLoftus-CheekAverage rating
Squad number14Player nameChalobahAverage rating
Squad number22Player nameZiyechAverage rating
Squad number10Player namePulisicAverage rating
Squad number29Player nameHavertzAverage rating
Squad number27Player nameFofanaAverage rating
Squad number15Player nameMudrykAverage rating
Squad number33Player nameFofanaAverage rating
- Line-upsMatch StatsLive Text
1de Gea29Wan-Bissaka19Varane2Lindelöf23Shaw18Casemiro14Eriksen21Antony8Bruno Fernandes25Sancho9Martial
- 1de Gea29Wan-Bissaka19Varane2Lindelöf23ShawSubstituted forMalaciaat 45'minutesBooked at 75mins18Casemiro14EriksenSubstituted forFredat 70'minutes21AntonySubstituted forRashfordat 29'minutes8Bruno FernandesSubstituted forMcTominayat 86'minutes25Sancho9MartialSubstituted forGarnachoat 70'minutes
- 1Arrizabalaga28Azpilicueta33Fofana14Chalobah67Hall30ChukwuemekaSubstituted forLoftus-Cheekat 82'minutes5FernándezBooked at 75mins23GallagherSubstituted forFofanaat 82'minutes31MaduekeSubstituted forZiyechat 82'minutes29HavertzSubstituted forJoão Félixat 64'minutes15MudrykSubstituted forPulisicat 64'minutes
- 6Thiago Silva10Pulisic11João Félix12Loftus-Cheek16Mendy22Ziyech26Koulibaly27Fofana58Gilchrist
Referee:Stuart AttwellAttendance:73,561Match StatsHome TeamMan UtdAway TeamChelseaPossessionHome41%Away59%ShotsHome18Away14Shots on TargetHome9Away5CornersHome3Away4FoulsHome12Away6Live Text Post update
Match ends, Manchester United 4, Chelsea 1.
Second Half ends, Manchester United 4, Chelsea 1.
Corner, Manchester United. Conceded by Kepa Arrizabalaga.
Attempt blocked. Marcus Rashford (Manchester United) right footed shot from outside the box is blocked. Assisted by Fred.
Attempt saved. Scott McTominay (Manchester United) right footed shot from the centre of the box is saved in the centre of the goal. Assisted by Jadon Sancho.
Attempt blocked. Christian Pulisic (Chelsea) right footed shot from long range on the left is blocked.
Attempt saved. Marcus Rashford (Manchester United) left footed shot from the centre of the box is saved in the bottom left corner. Assisted by Scott McTominay.
Corner, Manchester United. Conceded by Kepa Arrizabalaga.
Attempt saved. Alejandro Garnacho (Manchester United) left footed shot from the centre of the box is saved in the bottom right corner. Assisted by Jadon Sancho.
Goal! Manchester United 4, Chelsea 1. João Félix (Chelsea) right footed shot from outside the box to the bottom left corner. Assisted by Hakim Ziyech following a fast break.
Substitution, Manchester United. Scott McTominay replaces Bruno Fernandes.
Attempt blocked. Hakim Ziyech (Chelsea) left footed shot from outside the box is blocked. Assisted by David Datro Fofana.
Attempt blocked. Alejandro Garnacho (Manchester United) right footed shot from the centre of the box is blocked. Assisted by Marcus Rashford.
Substitution, Chelsea. Hakim Ziyech replaces Noni Madueke.
Substitution, Chelsea. Ruben Loftus-Cheek replaces Carney Chukwuemeka.
Substitution, Chelsea. David Datro Fofana replaces Conor Gallagher.
Foul by Christian Pulisic (Chelsea).
David de Gea (Manchester United) wins a free kick in the defensive half.
Goal! Manchester United 4, Chelsea 0. Marcus Rashford (Manchester United) left footed shot from very close range to the bottom left corner.
Attempt saved. Marcus Rashford (Manchester United) right footed shot from the centre of the box is saved in the bottom right corner. Assisted by Bruno Fernandes.
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