Match ends, Manchester United 2, Swansea City 0.
Romelu Lukaku scored his 100th Premier League goal as Manchester United strengthened their grip on second place and dented Swansea's survival hopes.
Lukaku gave United an early lead when he collected Alexis Sanchez's pass to fire in with the aid of a deflection.
Sanchez's crisp strike soon doubled the advantage - only his second league goal for United - as the hosts dominated.
Swansea improved after the break, Tammy Abraham twice denied by David de Gea, but United were always in control.
Jose Mourinho's side re-opened a two-point gap over third-placed Liverpool, who won 2-1 at Crystal Palace earlier on Saturday.
Swansea stay three points clear of the relegation zone, but drop down a place to 15th.
'Dream come true' - Lukaku
Belgium striker Lukaku has divided opinion among Manchester United fans at times during his first season following the £75m move from Everton last summer, but again demonstrated his quality with a clinical strike that set them on the way to a comfortable win.
Lukaku took one touch to control Sanchez's pass, creating space inside the Swansea box to hammer in.
It was richly deserved lead for the home side, who started the game at a high tempo, and one which they never looked like relinquishing.
Lukaku has now scored 26 goals for the club this season, despite suffering some criticism after scoring just once in 12 games in October and November.
The 24-year-old, who has also played for Chelsea, West Brom and Everton, becomes the youngest foreign player to reach a century of Premier League goals.
"I'm really happy to achieve that milestone," he said.
"It is a dream come true. l'm really happy to achieve that in a league I've wanted to play in since I was six years old."
United strengthen grip on top four
United's hopes of catching runaway leaders Manchester City may have long gone, but there is still plenty to play for as they aim to finish runners-up behind their neighbours.
Second place would represent their highest league finish since winning the title in 2012-13 in Sir Alex Ferguson's final season at the helm.
But, after a Champions League last-16 exit against Sevilla and accusations of playing "boring" football, Mourinho has faced criticism in his second season in charge.
His team threw off the shackles from the start of Swansea's visit, however, playing the attacking football craved by the Portuguese's critics as they created numerous scoring chances in the early stages.
Lukaku provided the focal point with his endeavour, complementing the energy offered by Sanchez and Jesse Lingard - who followed up a productive international week for England with another eye-catching display.
Swansea could have been buried by a first-half United performance that Mourinho described as "perfect", although they fought back after the break as the home side eased off.
Nevertheless, Mourinho was happy with side's overall display - and again defended their league record this season.
"Last season we won titles but finished sixth in the league," he said.
"We want to finish second this year and have 10 points more than last season, more goals scored, less goals conceded, but there is a club which is making it practically impossible to follow. In other leagues we would be fighting for the title.
"We are having a positive season and we still have the FA Cup to come. We are going to fight for our presence there."
Carvalhal still confident of survival
Swansea have been revitalised since Carlos Carvalhal took over in December, winning five of their opening 10 Premier League matches under the former Sheffield Wednesday manager.
The Welsh club were bottom of the league, four points adrift of safety, before Carvalhal's appointment renewed hopes of avoiding the drop.
However, they never looked like boosting their points tally at Old Trafford - a ground where they had fared well in recent seasons with two wins and a draw in their past five visits.
Carvalhal's side were out-thought and out-run by United in the first half, failing to muster a single shot at goal as the home side controlled the game.
After bringing on striker Tammy Abraham and midfielder Tom Carroll at half-time, they improved considerably in the second half and offered more attacking threat as they searched for what had seemed an unlikely way back into the game.
England striker Abraham twice thought he had halved the deficit with sharp strikes, only to see United keeper De Gea - who had barely been involved up to that point - deny him.
"I have good expectations for the future as I think if we will play like that then we will stay in the Premier League," said Carvalhal.
Man of the match - Jesse Lingard (Manchester United)
More travel trouble for Swansea - the stats
- Romelu Lukaku is the 28th different player, first Belgian and fifth youngest to score 100 Premier League goals.
- Manchester United have won all three meetings with Swansea in all competitions this season, scoring eight goals and conceding none.
- The Red Devils have won each of their last five Premier League home games, netting exactly twice in each of the last four.
- Swansea have won just one of their last 14 Premier League away games, drawing four and losing nine.
- The Swans had as many shots on target in this game - two - as they had managed in their three previous Premier League away games.
- Alexis Sanchez had a hand in more Premier League goals in the opening 20 minutes of this match (one goal and one assist) than he had in his previous six appearances (one goal).
- Jose Mourinho is unbeaten in all 10 of his previous meetings with Swansea in all competitions, beating five different managers in that time.
For United, it is the derby. Mourinho's side making the short trip to neighbours Manchester City on Saturday, 7 April (17:30 BST).
Meanwhile, Swansea face a game that could have a huge bearing on their survival hopes when they travel to bottom side West Brom earlier the same day (15:00).
- 1de Gea
- 25A Valencia
- 8MataSubstituted forMcTominayat 90+1'minutes
- 14LingardSubstituted forHerreraat 76'minutes
- 7SánchezSubstituted forRashfordat 75'minutes
- 40Castro Pereira
- 5van der Hoorn
- 12DyerSubstituted forAbrahamat 45'minutes
- 4Ki Sung-yuengSubstituted forCarrollat 45'minutes
- 17ClucasSubstituted forRoutledgeat 56'minutes
- 19A Ayew
- Robert Madley
- Shots on Target
Second Half ends, Manchester United 2, Swansea City 0.
Corner, Swansea City. Conceded by Ashley Young.
Substitution, Manchester United. Scott McTominay replaces Juan Mata.
Corner, Manchester United. Conceded by Federico Fernández.
Romelu Lukaku (Manchester United) wins a free kick in the defensive half.
Foul by Federico Fernández (Swansea City).
Ashley Young (Manchester United) wins a free kick in the defensive half.
Foul by André Ayew (Swansea City).
Offside, Manchester United. Paul Pogba tries a through ball, but Juan Mata is caught offside.
Attempt saved. Romelu Lukaku (Manchester United) left footed shot from the centre of the box is saved in the centre of the goal. Assisted by Paul Pogba.
Paul Pogba (Manchester United) wins a free kick in the attacking half.
Foul by André Ayew (Swansea City).
Foul by Ander Herrera (Manchester United).
Kyle Naughton (Swansea City) wins a free kick in the defensive half.
Substitution, Manchester United. Ander Herrera replaces Jesse Lingard.
Substitution, Manchester United. Marcus Rashford replaces Alexis Sánchez.
Offside, Manchester United. Alexis Sánchez tries a through ball, but Nemanja Matic is caught offside.
Juan Mata (Manchester United) wins a free kick in the attacking half.
Foul by Mike van der Hoorn (Swansea City).