Swansea stunned Manchester United for the third consecutive time with another comeback win at the Liberty Stadium.

Juan Mata's close-range strike just after half-time put United ahead, but Andre Ayew and Bafetimbi Gomis gave Swansea a 2-1 victory which moved them above the Red Devils and into the top four of the Barclays Premier League.

Gomis had scored the winner when the two sides last met in February, part of a Swansea double, and he did so again with his fourth goal of the season and his ninth in the last 10 Premier League games.

It all added up to another feather in the cap of Swansea manager Garry Monk and a desperate afternoon for Louis van Gaal, who was taking charge of United for the 50th time, and saw his side concede for the first time in the league this season.

United had scored four times in the Champions League in midweek and they started where they left off in Bruges, full of attacking intent and trying to get the ball into lone striker Wayne Rooney quickly.

SEE MORE: Swansea’s 2015/16 season preview.

Memphis Depay won a second-minute free-kick which he took and forced Lukasz Fabianski into a scrambling save on his goal-line and Mata was almost instantly off target from 20 yards.

Luke Shaw then released Rooney with a peach of a pass which cut out Federico Fernandez but Ashley Williams covered brilliantly to avert the danger.

United were at their most dangerous when Memphis was drifting off the left flank and from one such foray he picked out Herrera, but Mata was unable to profit from his fellow Spaniard's pass as he fired wide of the near post.

Swansea had been slow to stir with some of their early-season attacking fluency denied them by the absence of thigh injury victim Jefferson Montero.

But the hosts suddenly took a grip of the game at the halfway point of the first half after Gomis had raced onto Ayew's pass to shoot wide.

Seconds later Gomis' clever flick freed Gylfi Sigurdsson and the resulting snapshot was inches wide of the post.

SEE MORE: Manchester United’s 2015/16 season preview.

But United were clearly rattled and Sergio Romero's poor clearance straight at Jonjo Shelvey ended with the goalkeeper having to clutch the midfielder's shot under his crossbar.

Swansea were even closer to breaking the deadlock after 28 minutes when Gomis' purposeful run left Daley Blind and Chris Smalling struggling to cope and the Frenchman poked the ball against the outside of Romero's post.

But United were ahead when Shaw surged down the left and his cross fell to Mata at the far post who crashed the ball high into the net under pressure from Williams.

Mata might have had another but Swansea equalized from a 61st-minute counter-attack when Williams fed Sigurdsson and Ayew's downward header from his cross had too much power for Romero.

And they were ahead five minutes later when Shelvey and Sigurdsson combined for Ayew to slip through Gomis.

The Frenchman's finish lacked but it still squirmed its way past Romero at the keeper's near post and victory was preserved by Williams' terrific tackle at the death to deny Rooney.

TWEET OF THE MATCH

"Great pass from Ayew but the @ManUtd defense & keeper will not be happy with that goal at all. Sensed the danger – deal with it" – former United defender @rioferdy5 on the winning goal.

MATCH HIGHLIGHTS

PLAYER RATINGS

Swansea

Lukasz Fabianski: 7 (out of 10)

Kyle Naughton: 7

Federico Fernandez: 7

Ashley Williams: 7

Neil Taylor: 7

Jack Cork: 7

Jonjo Shelvey: 7

Gylfi Sigurdsson: 7

Wayne Routledge: 6

Andre Ayew: 8

Bafetimbi Gomis: 7

Subs

Ki Sung-yueng: 7

Eder: 6

Kyle Bartley: 6

Manchester United

Sergio Romero: 4

Matteo Darmian: 6

Chris Smalling: 6

Danny Blind: 5

Luke Shaw: 7

Morgan Schneiderlin: 5

Bastian Schweinsteiger: 6

Juan Mata: 6

Ander Herrera: 6

Memphis Depay: 5

Wayne Rooney: 6

Subs

Ashley Young: 5

Michael Carrick: 6

Marouane Fellaini: 5

STAR PLAYER

Andre Ayew: Enjoyed a wonderful battle with the impressive Luke Shaw and two moments of class saw him shade it. Showed his football intelligence to find space in the middle and claim his third Premier League goal with a firm downward header before setting up Bafetimbi Gomis' winner. Delicious ball into Gomis' stride ensured the Frenchman did not have to break stride before shooting.

MOMENT OF THE MATCH

Sweeping Swansea move for Gomis' winner. Jonjo Shelvey underlined his England credentials with a delightful ball into Gylfi Sigurdsson, who laid it off to Ayew. The Ghanaian spotted the run of Gomis, who had lost Chris Smalling, and although the finish lacked power it was still enough to embarrass United goalkeeper Sergio Romero at his near post.

VIEW FROM THE BENCH

Swansea manager Garry Monk would have been disappointed to lose in-form winger Jefferson Montero to a training-ground thigh injury the day before the game but there is plenty of depth to his squad these days. Ki Sung-yueng underlined that when he came off the bench to play an integral role. Louis van Gaal had seen United keep three clean sheets in the Premier League but doubts over his side's defensive capabilities surfaced as his central defenders went AWOL and his goalkeeper had the wobbles.

MOAN OF THE MATCH

How galling must it be for United fans to see David de Gea banished to the sidelines as Sergio Romero dons the goalkeeping gloves? De Gea might be heading for the Old Trafford exit door with Real Madrid waiting in the wings, but it is far from clear whether Romero is the long-term answer. Kept three clean sheets with barely anything to do in his opening Premier League matches but exposed here and might well have stopped both Swansea goals.

WHO'S UP NEXT

Manchester United v Liverpool (Premier League, Saturday, September 12)

Watford v Swansea (Premier League, Saturday, September 12)

United boss Van Gaal said: They changed their shape at 1-0 and we couldn't cope with them. That's not good because we were only five minutes from a draw.

"I think we controlled the game and played very good but you have to be compact. Swansea were compact in the last 35 minutes.

"We could have scored more, I don't think that's the problem. When you create chances that is the biggest issue. You also need a bit of luck."

On the goals his team conceded, the Dutchman added on Sky Sports: "I have to analyze the goals with my players" – but he will not plan any panic signings before the transfer window closes.

He said: "Today doesn't have any effect, when you are scouting players you know a month or two in advance which players you can buy or not. It's not about the last moment."

Swans boss Monk said of his team: "We've had a good start and we will work hard to try to kick on when we come back from the international break.

"We have no doubt about the players committed to us today. We don't need anyone to come in at this point. I'm very happy with the squad, we want to have a good season.

"We work very hard on and off the field. We've performed unbelievably well and showed every single side of us. That's what every good side should be doing."