Ilias Chair’s goal took QPR into the top half of the Championship.
It was an unhappy return for Gareth Ainsworth to Loftus Road, where the Wycombe boss was a fans’ favourite during seven years as a player at QPR and also had two spells as caretaker manager.
Rangers’ win was their sixth in nine matches and the clean sheet their third in their past five games.
Chris Willock was the architect of their 23rd-minute winner, superbly evading two challenges on the right and then shooting past keeper David Stockdale at the near post for Chair to add the finishing touch from virtually on the goal-line.
QPR had been on top, with Stefan Johansen just unable to get to Lee Wallace’s left-wing cross and soon afterwards bringing a save from Stockdale with a left-footed strike.
The visitors responded well to going behind and enjoyed a decent spell of pressure in which Anis Mehmeti’s shot was pushed away by Rangers keeper Seny Dieng.
But that was a rare attack by the Chairboys, who were on the back foot again after the interval.
Charlie Austin fired over as Rangers continued to dominate, and Chair shot against the outside of the near post after being set up by Rob Dickie.
QPR hit the post again when Willock steered his shot against the woodwork after a pull back from the left by Wallace, who was found by Johansen’s clever pass.
And Dickie headed wide from a cross by fellow centre-back Yoann Barbet as the hosts searched in vain for a second goal.
QPR (3-4-2-1): Dieng; Dickie, De Wijs (Kakay 77), Barbet; Kane, Johansen, Field, Wallace; Chair (Cameron 65), Willock (Adomah 88); Austin (Dykes 65).
Subs not used: Lumley, Thomas, Hamalainen, Ball, Bonne.