Eric Bailly opened the scoring for United in the final minute of the first half, but Swansea remained competitive during the majority of the second period.
Read below to see how the action unfolded at the Liberty Stadium.
11.31amHello, and welcome to Sports Mole's live coverage of the match in the Premier League between Swansea City and Manchester United.
11.34amThe opening weekend of the new Premier League season ended with Manchester United thrashing West Ham United, so it is almost fitting that the most impressive performers of Matchday One begin the action on Matchday Two. The confidence will be flowing through the ranks at Old Trafford and Jose Mourinho's side are justifiably the clear favourites to prevail at the Liberty Stadium.
11.37amAs for Swansea, they will also take confidence from how they performed last weekend after they returned from St Mary's with a goalless draw against Southampton. Head coach Paul Clement has spoken of his desire to reach 40 points and move on to bigger things this season and results on the road will only help their quest to stay clear of the relegation zone.
11.38amAnyway, it is team news time. Will either boss dare change their starting lineup after last weekend? Let's find out...
11.39amSWANSEA CITY XI: Fabianski, Naughton, Fernandez, Bartley, Mawson, Olsson, Roque Mesa, Fer, Carroll, Ayew, Abraham
11.40amSWANSEA CITY SUBSTITUTES: Nordfeldt, Rangel, van der Hoorn, Fulton, Narsingh, Routledge, McBurnie
11.41amMANCHESTER UNITED XI: De Gea, Valencia, Bailly, Jones, Blind, Matic, Pogba, Mata, Mkhitaryan, Rashford, Lukaku
11.42amMANCHESTER UNITED SUBSTITUTES: Romero, Lindelof, Smalling, Herrera, Fellaini, Lingard, Martial
11.46amLet's start with the home side as Clement makes two alterations. One is enforced with Leon Britton struggling with injury, but Wayne Routledge drops down to the bench. Coming into the side are Kyle Bartley, who spent last season on loan at Leeds United, and Roque Mesa, the Spaniard who has been signed from Las Palmas for £11m and makes his debut. Tammy Abraham keeps his role in attack with Fernando Llorente still out injured, while Jordan Ayew gets another chance to add to his solitary goal since joining from Aston Villa in January.
11.49amAs for United, Mourinho selects an unchanged starting lineup, which comes as no surprise at all. There is, however, a change on the bench with summer signing Victor Lindelof coming in for Matteo Darmian. Ander Herrera also has to make do with a place among the replacements.
11.53amHEAD TO HEAD! Today's match represents the 30th time in which these two teams have met in a competitive fixture, with United claiming 13 wins in comparison to 10 victories for Swansea. In 12 matches since Swansea's promotion to the Premier League, Swansea have prevailed one three occasions and recorded one draw, with two of the last three meetings at the Liberty Stadium ending in a home success.
11.57amHowever, while two of the last three matches have ended in a home win, last season's clash ended in a convincing triumph for Manchester United thanks to three goals in the opening 33 minutes. Paul Pogba opened the scoring before Zlatan Ibrahimovic added two goals before half time. Click here to read back on the report from that match.
12.02pmAfter United's 4-0 win over West Ham, it was Lukaku who gained most of the plaudits for scoring two goals in the opening hour of his debut, but it was fellow arrival Nemanja Matic who ticked a lot of boxes for what United were missing last season. His interceptions, and short and incisive passes, will prove vital in this team and the centre of the park will only become more formidable when Mourinho decides to pair the Serbian with Ander Herrera. There will be a time and a place for that partnership but in games such as this one, Matic is the perfect foil for Paul Pogba and Juan Mata to press on and help the attack. Leroy fer and Tom Carroll have got a tough job on their hands...
12.06pmIt has been an open secret that Swansea would be without Gylfi Sigurdsson this season but today is the first game where the Icelandic playmaker will have no influence whatsoever on this squad. Clement has an almost impossible job in replacing the club's key man, but it is something which needs to be achieved sooner rather than later. Their lack of creative threat was on show against Southampton and while it sounds like Nacer Chadli may be on his way from West Bromwich Albion, there is a feeling that they may need another influence in behind the strikers.
12.10pmAt the back, Swansea fans will get to see Kyle Bartley in the starting lineup for the first time since an FA Cup defeat to Oxford United in January 2016. You would like to think that the 26-year-old has only benefited from playing 45 games in the Championship last season, but this is a big step back up for the centre-back, especially when featuring in a back three rather than a back four.
12.15pmIt is still early days but a win for United would put pressure on their rivals. Not only would it see the North-West outfit sit at the top of the table ahead of the remainder of the weekend fixtures, it would leave the likes of Manchester City, Arsenal and Tottenham Hotspur all having to come through tricky encounters to match them. Again, early days and all that, but each of the title-chasing clubs will want as many points on the board as possible before the European schedule begins next month.
12.20pmFrom a Swansea perspective, they are probably of the view that they would be delighted with a point from this match. United's performance last week was efficient and clinical, and they are probably going to be difficult to stop this afternoon. It will be interesting to see how Tammy Abraham copes in attack because the Chelsea loanee may find himself having to do a lot of work on his own if his teammates sit too deep.
12.23pmPREDICTION! With that in mind, we can only predict an easy United victory. Lukaku looks "on it" and with the rest of the team seemingly coming together, don't be surprised to see him back another double in south Wales. United to claim a 3-0 triumph.
12.27pmThe two teams have made their way out at the Liberty Stadium. The home fans are buzzing for this fixture and who wouldn't be after they needed to travel to Southampton on the first day of the campaign. However, how long will that enthusiasm last? Let's find out.
1 minSwansea get us underway.
2 minIt has been a really positive start from Swansea who are looking to press United back in these early stages. Carroll looks particularly lively but he can't collect the ball in time to cross into the middle.
3 minWOODWORK! Ayew looks like he is carrying a bit of timber but he has just nearly scored an outrageous goal. I can't make out if he is trying to cross the ball without the outside of his foot, or shoot, but his effort beats De Gea, clips the underside of the crossbar and goes clear.
4 minStraight after that, United broke quickly through Lukaku but the Swansea defence got back well before the Belgian sliced an effort well wide of the target.
7 minSHOT! Rashford turns well on the edge of the area and it gives him a chance to get a shot on goal from 20 yards out. However, he doesn't make the sweetest of connections and his effort goes wide of the post.
9 minWOODWORK! Now United hit the woodwork! A free kick is dinked in by Mata but Jones somehow hits the bar from no more than eight yards out. It should be a goal, and replays show he was offside.
13 minIt's very much all United now. The game is being played at the tempo and pattern we suggested in our build-up. Abraham is trying to be clever when chasing endless balls but it is giving United an easy route into the midfield.
17 minThere's already a sense of frustration emanating from the stands at the Liberty Stadium. I think Ayew's effort which hit the crossbar has got the supporters hopes up. It's still all United who must have had 75% of the possession.
20 minUnited are always looking for the pass which gets Lukaku on the ball in the penalty area and it takes a fantastic block from a defender to prevent the Belgian from getting an effort on target. The pressure continues to build on Swansea.
23 minIt might take something spectacular to get Swansea on the scoresheet this afternoon and Olsson has just attempted something of that ilk. I think it was supposed to be a cross but his overhead kick from an acute angle almost goes over De Gea, with the goalkeeper having to claim well.
26 minBOOKING! This is so needless and so cynical from Pogba. He goes into the book for a crude swipe of Carroll's legs.
30 minYou certainly can't be critical of Swansea's work-rate and how Clement has got his side well-drilled, but there's an inevitably about United getting on the scoresheet. They aren't exactly creating a hatful of chances but they look threatening every time they go forward.
31 minPogba is getting a talking to from the referee. He should be grateful that he is because on another day, the Frenchman would be receiving a second yellow. It's another needless late challenge and while there was little malice in it, there was also little intent to play the ball.
33 minAyew is drifting in and out of this game but he does superbly to take the ball all of 40 yards before delivering a low cross into the area. The cross is intended for Abraham but United manage to get the ball behind for a corner.
34 minCHANCE! From the resulting set piece, Bartley rises above Bailly but he directs his header wide of the far post. That was a chance.
36 minCHANCE! You'd fancy Rashford to score from most one-on-one chances he receives but after capitalising on Mawson's poor header, he clips the ball straight into the hands of Fabianski.
38 minCHANCE! Back come Swansea who should probably score at the back post when a free kick finds both Bartley and Fernandez in space. However, Bartley gets in the way of his teammate and the opportunity goes begging.
42 minThere are less than five minutes to go in this first half and if Swansea can get to the break without conceding, it will be job well done. This has been an entertaining 42 minutes of football.
42 minCHANCE! Fabianski nearly gifts United a goal after coming out to claim a cross and dropping it under pressure from Pogba. It falls to Mata but the Spaniard hooks wide from around 14 yards.
45 minGOAL! Swansea City 0-1 Manchester United (Bailly)
45 minDisaster for Swansea. In the final minute of normal time, Pogba meets a corner and sends a header towards goal. Fabianski pulls off a stunning save to tip the ball onto the crossbar but Bailly has the simplest of tasks of converting the rebound from on the line.
45+1 minHALF TIME: Swansea City 0-1 Manchester United
1.19pmThe half-time whistle goes at the Liberty Stadium and United deservedly lead thanks to Bailly's first goal for the club. Swansea have had openings of their own but it has been the visitors who have looked the most likely to score, and they did just that in the final minute of the half.
46 minUnited get us back underway.
48 minIt has been a relatively quiet start to the second half. United came out firing without create anything, while Olsson has wasted a crossing opportunity for the home team.
51 minSwansea are defending the end of the pitch where the Sun is causing a bit of havoc, and United look intent on delivering as many crosses as possible. Mourinho's men look back in their groove after the restart.
55 minSwansea have plenty of pace on the bench in Routledge and Narsingh and you feel as though they will have to use one or both of the wingers sooner rather than later. The home team look flat in attack now and United have the confidence to throw their full-backs further forward.
56 minSHOT! Rashford continues to look United's most likely scorer of a second goal but when having the chance to shoot on goal from 20 yards, his low attempt is straight at Fabianski.
58 minSHOT! Things feel that desperate for Swansea right now that Fer has just attempted a 25-yard half-volley on a partial turn. It was only going to end up in the stands.
61 minCHANCE! Much, much better from Swansea. Carroll's driven cross finds the head of Abraham, but the Chelsea loanee powers his effort just over the crossbar from 12 yards.
64 minSwansea have started to some more ambition in the final third. Ayew is popping up in spaces which are troubling United and forcing them onto the back foot but on this occasion, he perhaps takes a touch too many when trying to pass to Abraham.
66 minAyew is again in the thick of the action but this time, it's Abraham's fault for not gambling to meet a low delivery across the six-yard box.
67 minSUBSTITUTIONS! Time for some Swansea changes, with Bartley and Musa being withdrawn for Luciano Narsingh and Wayne Routledge.
71 minYou have to be impressed with this Swansea response. They were second best during the opening stages of the second half, but they are the better team now. Clement's team are just struggling to get a final touch at the end of promising situations.
73 minBOOKING! Fer goes into the book for Swansea after going in late on Blind when the left-back got a shot away.
74 minSHOT! From the resulting free kick, Pogba whips a free kick marginally over the bar from 25 yards.
75 minSUBSTITUTIONS! Two alterations for United now, with Marouane Fellaini and Anthony Martial replacing Mata and Rashford.
79 minUnited have began to rgain control of this contest over the past few minutes. They have found a balance with forcing Swansea to chase and with trying to net a game-deciding second.
80 minGOAL! Swansea City 0-2 Manchester United (Lukaku)
80 minGame over. Martial and Mkhitaryan combine to set up Lukaku all on his own in the penalty area, and the forward is left with the simple task of finding the corner from 12 yards.
82 minGOAL! Swansea City 0-3 Manchester United (Pogba)
82 minThis is harsh on Swansea but so clinical from United. Mkhitaryan is again the creator with his perfectly-weighted ball finding the run of Pogba who produces a fine finish inside the near post.
84 minGOAL! Swansea City 0-4 Manchester United (Martial)
84 minOk, so this is very harsh on Swansea. United come surging forward once again and after Pogba passes to Martial, the Frenchman does the rest as he cuts inside onto his right foot before finding the bottom corner of Fabianski's net.
90 minThere will be three minutes of added-on time.
90+3 minFULL TIME: Swansea City 0-4 Manchester United
2.25pmThe full-time whistle goes at the Liberty Stadium and United have registered their second successive 4-0 to move clear at the top of the table. Swansea did not deserve to lose by such a wide margin, but United were deserved victors in south Wales.
2.26pmThat will be all from Sports Mole for this match. Thank you for joining us this afternoon and we hope that you can stick around for our coverage of Liverpool's showdown with Crystal Palace. Goodbye for now.