Manchester United suffered only their second Premier League defeat since November

Manchester United suffered only their second Premier League defeat since November as Bafetimbi Gomis's second-half goal gave Swansea victory.

Ander Herrera's low strike put United ahead, but the hosts responded immediately as Ki Sung-yueng flicked in from Jonjo Shelvey's cross.

Louis van Gaal's side dominated the second period but failed to score.

Shelvey's 73rd-minute shot deflected off Gomis to give the Swans a first league double over United.

Defeat means United drop to fourth place in the Premier League - Arsenal leapfrogging them by beating Crystal Palace - and hampers their hopes of making an instant return to the Champions League after failing to qualify for Europe last season.

We forgot to score - Louis van Gaal

Swansea won 2-1 at Old Trafford on the opening day of the season to ruin Van Gaal's first competitive match as United boss.

And the Welsh club pained the Dutchman again by inflicting only a second defeat on United in 20 matches across all competitions.

The Red Devils' misery was compounded by the sight of Robin van Persie leaving the Liberty Stadium on crutches, with a protective boot around his right ankle after suffering a late injury.

The Netherlands striker had been recalled from injury as United made three changes from their FA Cup win at Preston.

There was a more radical alteration from Swansea, as manager Garry Monk switched to a midfield diamond for the first time.

Super Swansea
Swansea put two league goals past Manchester United at home for the first time since January 1982
Ki Sung-yeung has scored in back-to-back appearances at the Liberty Stadium for Swansea

And it was the hosts who made the stronger start.

Gomis had managed only one league goal before this match, but the France international striker could have scored twice in the opening 10 minutes.

His header from a Gylfi Sigurdsson corner was cleared off the line by Herrera, while he nodded over from Ki's flick on moments later.

Monk hails Swansea 'character'

United threatened sporadically as Van Persie's close-range effort grazed the crossbar and Wayne Rooney had his first shot on target of 2015, albeit a weak effort easily held by Lukasz Fabianski.

When the visitors' attacking talent finally clicked, they took the lead in fine fashion.

After Luke Shaw's burst down the left wing, a neat exchange of passes between Wayne Rooney and Angel Di Maria set up Herrera, whose low drive went in off the post.

But the lead lasted less than two minutes, as Shelvey's excellent cross was guided in by Ki.

After an open, fluid first half in which both sides pushed forward, United sought to control the contest after the interval by dominating possession.

Swansea dropped deeper as a result, seemingly inviting pressure, and there were scares for the hosts such as Marcos Rojo's missed free header.

Their resilience was rewarded with 15 minutes left, as Shelvey's 25-yard shot deflected off Gomis to seal Swansea's second win of the season over United.

Spanish midfielder Ander Herrera opened the scoring for Manchester United with a low drive

Ki Sung-yueng finished a flowing move to equalise for Swansea just minutes after United took the lead

United boss Van Gaal was in animated conversation with assistant Ryan Giggs

Louis van Gaal's side lost for just the second time in 20 matches