Match ends, Manchester United 4, Leicester City 1.
Manchester United thrashed Premier League champions Leicester City as boss Jose Mourinho dropped captain Wayne Rooney from his starting line-up.
Chris Smalling's header put United ahead before Juan Mata finished off a slick move with a crisp strike.
Marcus Rashford and Paul Pogba - with his first goal for the club - both scored from corners, with Demarai Gray's spectacular long-range strike the only consolation for Leicester.
Rooney came on in the 83rd minute.
United's first Premier League win in a month was sealed by half-time, but a third defeat for Leicester already matches their total for the whole of last season.
No Rooney, no problem
"If he has to go on the bench, he goes on the bench. If he has to stay at home, he stays at home."
Mourinho was true to his pre-match words as Rooney was dropped for a Premier League game for the first time since Boxing Day 2015 - and ended up a spectator for what was eventually a transformed first-half performance.
For the first 20 minutes it may have been more of the same from United - ponderous and slow in their approach - but once Smalling headed in Daley Blind's corner the shackles were released.
How much of a difference Rooney's absence made to their play is hard to quantify, but a 4-0 lead at the break was proof enough the change was justified.
Mata, nominally playing in Rooney's place behind Zlatan Ibrahimovic, was bright and lively and took his goal superbly before teeing up Rashford for a tap-in, but it was in midfield the hosts were able to really take a grip of the game as Leicester froze.
Rooney eventually came on with seven minutes left, replacing Rashford on the left wing. Where his future role now lies remains a mystery but Mourinho's decision to leave out his captain could hardly have worked out better.
A glimpse of Pogba's best
United's first-half performance was their best of the season so far, and went hand-in-hand with Pogba's finest display since his world-record move to Old Trafford this summer.
Mourinho chose Ander Herrera to partner him instead of Marouane Fellaini or Michael Carrick, and Pogba played noticeably further forward, often interchanging with Mata.
He had already played two searching cross-field passes before a flurry of individual highlights as United scored three goals in five dazzling minutes at the end of the first half.
Pogba delivered a disguised chip over the top to Ibrahimovic, who volleyed over, fired in a dipping 35-yarder that was well saved by Ron-Robert Zieler, and sliced through a pass that freed Antonio Valencia. The Frenchman then played a key part in Mata's second before he headed his first goal for the club.
For £89m he is expected to control games, and he did for a brilliant spell.
He was anonymous after the break but the game was already won.
Foxes need to fix their defence
Leicester's shock title win last season was built on the back of the attacking brilliance of Jamie Vardy and Riyad Mahrez, coupled with the work ethic of the now departed N'Golo Kante, but also on a solid defence, which conceded just 36 goals in 38 games.
The Foxes won five of six games 1-0 in March and April to move towards the championship as they conceded four goals in seven games.
Yet here they became the first defending Premier League champions to concede four goals in a single half.
What will hurt manager Claudio Ranieri even more is that, apart from Mata's brilliantly constructed and taken second goal, the other three were simple goals from corners which could, and should, have been stopped.
The Foxes collapsed after the opening goal and the message was clear at half-time when star men Vardy and Mahrez were taken off, apparently rested for the Champions League date with Porto in midweek.
Man of the match - Paul Pogba (Manchester United)
BBC Sport's Simon Stone at Old Trafford
There is no great disconnect between Wayne Rooney and club or manager, as there was in 2013, when Rooney sat in an executive box and watched Sir Alex Ferguson's final Old Trafford game as Manchester United manager behind glass.
Rooney politely applauded back when he was sent out to warm up for the first time, and the home fans' reception was enthusiastic when he ran on to the field after replacing Rashford near the end.
It won't stop the chatter around Rooney though. His United future is on the line.
Mourinho's decision is not about this lunchtime - or Thursday, when United face Zorya Luhansk in the Europa League and Rooney is likely to start.
It is about next month, and January and June next year. About the day when Henrikh Mkhitaryan is going to be fit and in form. When transfer windows open and close.
Rooney did not get dropped for the man Mourinho bought to be his new number 10. He got dropped because Mourinho needed to do something to wake his team from their September slumber.
What we don't know yet is whether England's captain is surplus to requirements permanently.
What they said
Manchester United manager Jose Mourinho:
"Today we had intensity, movement and dynamism. To be back home and beat the champions is good. Last season we couldn't beat them and this season we have beaten them twice already."
Leicester boss Claudio Ranieri:
"It is not possible to concede three goals from corners. That means you are not concentrating. We are usually very solid at corners and free-kicks, it was very strange. Until now we have been very strong, we have made some mistakes. I can understand that they score with headers, that they are very tall, but to score a smart goal from a corner is not possible.
"It is important to clean our mind and get ready for the Champions League on Tuesday."
Leicester host Porto in their first home game in the Champions League on Tuesday, while Manchester United welcome Ukrainian side FC Zorya Luhansk to Old Trafford in the Europa League on Thursday.
- 1de Gea
- 25A Valencia
- 14LingardSubstituted forCarrickat 78'minutes
- 8MataSubstituted forYoungat 87'minutes
- 19RashfordSubstituted forRooneyat 83'minutes
- 17SimpsonBooked at 74mins
- 6HuthBooked at 50mins
- 26MahrezSubstituted forKingat 45'minutes
- 11AlbrightonSubstituted forSchluppat 62'minutes
- 9VardySubstituted forGrayat 45'minutes
- Mike Dean
- Shots on Target
Second Half ends, Manchester United 4, Leicester City 1.
Offside, Manchester United. Wayne Rooney tries a through ball, but Antonio Valencia is caught offside.
Ander Herrera (Manchester United) wins a free kick in the attacking half.
Foul by Daniel Amartey (Leicester City).
Ashley Young (Manchester United) wins a free kick on the right wing.
Foul by Robert Huth (Leicester City).
Foul by Chris Smalling (Manchester United).
Islam Slimani (Leicester City) wins a free kick in the defensive half.
Substitution, Manchester United. Ashley Young replaces Juan Mata.
Attempt saved. Zlatan Ibrahimovic (Manchester United) right footed shot from the left side of the box is saved in the centre of the goal. Assisted by Paul Pogba.
Substitution, Manchester United. Wayne Rooney replaces Marcus Rashford.
Offside, Manchester United. Marcus Rashford tries a through ball, but Zlatan Ibrahimovic is caught offside.
Corner, Leicester City. Conceded by Antonio Valencia.
Attempt blocked. Daniel Drinkwater (Leicester City) left footed shot from outside the box is blocked.
Corner, Leicester City. Conceded by Daley Blind.
Substitution, Manchester United. Michael Carrick replaces Jesse Lingard.
Corner, Leicester City. Conceded by David de Gea.
Attempt saved. Demarai Gray (Leicester City) right footed shot from long range on the left is saved in the top right corner. Assisted by Jeffrey Schlupp.
Corner, Manchester United. Conceded by Wes Morgan.