The Red Devils temporarily moved eight points clear of second-placed Manchester City thanks to a goal in each half from Wayne Rooney and Paul Scholes as the chances of a 20th league title received a boost.
United had bossed possession in the opening stages and deserved to go ahead, but not in the fashion they did, when referee Lee Mason awarded a questionable penalty and sent Shaun Derry from the pitch after he made minimal contact with Ashley Young just inside the area. Replays showed that Young was well offside when he was receiving Wayne Rooneyâ€™s through ball and Derry had only placed a hand on the back of the winger who went down way too easily.
Nevertheless, Rooney stepped up to the spot and dispatched the ball low and hard to Paddy Kennyâ€™s right to give the reigning champions a 15th minute lead.
United were in control throughout and with just over 20 minutes from time, Paul Scholes essentially wrapped it up when he received a pass from Rafael about 20 yards out and hammered home with a first-time effort which gave Kenny no chance at all.
Earlier, the QPR keeper had done well to deny the home side on a few occasions, namely when h produced a quality save to deny Rooneyâ€™s curling free-kick in the 7th minute before Rooney attempted a clever dink which was headed for the top corner until Kenny intervened.
United had the ball in the back of the net almost immediately after the restart when Antonio Valencia found Danny Welbeck but the flag was straight up for offside.
Rafael should have added a second when he was played through by Scholes in the 59th minute but Kenny was able to deflect the close range effort up onto the crossbar moments before the Râ€™s gloveman denied Welbeckâ€™s shot from the left side of the area and then was able to hang onto the England youngsters follow-up attempt.
With ten minutes left, Michael Carrick was desperately unlucky when his thunderous drive from way out cannoned into the upright having beaten Kenny but the job was already done as Sir Alex Fergusonâ€™s men put themselves in pole position for the trophy whilst Mark Hughesâ€™ Râ€™s kept their head above water by remaining 17th on the table.
TRIBAL ASKS: Did the sending off of Derry have any impact on todayâ€™s result or were United always going to come away from this one with maximum points?
Old Trafford, Manchester â€“ 75,505
Yellow cards: MANU - Rafael 73â€™
QPR - nil