United full back Rafael slammed a stunning half-volley in to the top corner from 25 yards to put United ahead in the 23rd minute on a cagey afternoon in west London.
Ryan Giggs sealed the points for the league leaders 10 minutes from time as he beat QPR’s offside trap to sweep the ball home.
The only concern for United will be the apparent back injury that forced top scorer Robin van Persie off five minutes before halftime after a collision on the touchline.
The result leaves United with a 15 point advantage over closest rival Manchester City before Roberto Mancini’s men take on Chelsea at the Etihad Stadium on Sunday.
It was yet another efficient performance from the champions elect as they extended their unbeaten run to 15 league matches and marched one game closer to a 20th English title.
QPR, for their part, remain rock bottom in the Premier League and look increasingly doomed.
After a tepid start to the game, United took the lead in the 23rd minute with a goal from nowhere. Julio Cesar parried away van Persie’s initial cross and the ball fell for Rafael to crack an outstanding half-volley into the top corner from 25 yards. The Brazilian will never score a better goal in his life.
A swift United move ended with Cesar producing a fingertip save to keep out van Persie’s cushioned volley after the Dutchman latched on to a cross from Rafael.
It was van Persie’s last real involvement of the afternoon as he was substitute five minutes before the break with a back injury he appeared to pick up in an innocuous collision with a photographer in the build-up to United’s opener.
The action barely picked up in the early stages of the second half and Redknapp responded on the hour mark by bringing on January signing Loic Remy for the injured Zamora.
The Frenchman almost made an immediate impact when he cut in from the left and saw his powerful near-post shot saved by David De Gea in the United goal.
Yet as QPR attacked, the game opened up for United on the counter-attack and Ferguson’s side took advantage 10 minutes from time.
Nani played in Giggs and the 39-year-old used all of his experience to beat the offside trap and slot his finish past Cesar.