Manchester United
Manchester United's Robin van Persie shoots at goal during his side's Premier League clash against Swansea City on SaturdayReuters

Manchester United are sweating on the fitness of striker Robin van Persie after Dutchman was seen on crutches, following the Red Devils' 1-2 Premier League defeat to Swansea City at the Liberty stadium on Saturday.

The 31-year-old striker, who returned to the squad after missing United's FA Cup win over Preston North End with a minor knock last week, picked up an injury during the closing stages of the game.

As manager Louis van Gaal had already made three substitutions he could not be replaced, and the match finally ended with 10-man United losing 1-2 to the Swans.

Although van Gaal did not reveal any details about van Persie's injury in the post-match conference, it is believed that the Dutchman has damaged his right ankle, which was in a protective boot.

Meanwhile, this defeat has dented United's chances of making a top four finish in the Premier League.

Ander Herrera put United ahead in the 28th minute, but Ki Sung-Yeung immediately levelled the scores after a couple of minutes. Although United dominated possession and created a lot of chances in the second half, it was Bafetimbi Gomis who netted the winner for Swansea City in the 73rd minute.

And van Gaal rued his side's inability to find the nets.

"I think it was our best second-half [performance], we created a lot of chances and dominated the game but we didn't score," the manager told MUTV. "That's football, you have to score out of the chances you create. We had a lot of chances, especially in the second half, but they scored and then you know that it shall be difficult."

However, the Dutchman did take some positives from the game, insisting that he was pleased with his side's dominating display away from home.

"I shall say to the players that it is very disappointing but, in the process of the development of our play, then it was a very good match," the Dutchman added. "To play like this, so dominant, creating so many chances, you can hardly improve apart from scoring goals, but that is also a bit of luck."