A first minute strike from Wayne Rooney, who later went off injured, was enough to leave Manchester United just two points behind leaders Liverpool. Reds boss Sir Alex Ferguson expects Rooney to be out for around three weeks, after the striker suffered a hamstring injury.

"It is a hamstring injury," Ferguson confirmed. "That will be about three weeks. We hope it is no longer."

United always looked in control against a hard working Wigan side but Antonio Valencia nearly grabbed the visitors a point but blazed over the bar late on.

Ferguson told Sky Sports, "We had a few injuries tonight.

Some of our players were limping through the last 25 minutes and it was becoming a bit of a worry.

"Carlos Tevez then came on, did fantastically, but picked up an injury as well - so it was a tough night for us." The Scot was just relieved to pick up the three points.

"It was as tough as I could have possibly expected.

"We had to dig really deep and show good character. There have been many occasions over the years when we have won 1-0 and they have gone on to be vital results, and tonight's is certainly a very important victory.

"Nemanja Vidic was fantastic for us and epitomised the character we had to show to pick up the win. Wigan were absolutely terrific tonight." Ferguson continued, "We need to kick on now - this is the time. The games come pretty quickly and we now go to Bolton on Saturday, which is always a tough game.

"The games really come at you thick and fast and we just have to cope with it."