LATICS slipped to their first defeat in 11 matches thanks to Yossi Benayoun’s early goal in West London.
The FA Cup holders held their own for the majority, but paid a high price for not taking the chances that came their way.
After falling behind, Latics created several chances to equalise, only for James McClean, James Perch and James McArthur to find former England goalkeeper Rob Green in inspired form.
When Green was finally at the start of the second period, Ivan Ramis’ header came back off the crossbar and away to safety.
Rangers then hit the woodwork themselves when Ravel Morrison’s sumptuous free-kick beating Ali Al Habsi but not quite finding the net.
The stoppage-time sending-off of Benayoun sadly came too late to make a real difference, with substitute Nicky Maynard’s late header being superbly parried away by the excellent Green.
Latics had gone into the game knowing a win would lift them to within a point of fourth-placed Rangers with a game still in hand.
But they were behind inside 15 minutes, thanks to a well-worked goal from the home side.
Tom Carroll’s cross from the left was touched on by Clint Hill for Benayoun to slot into the bottom corner past Al Habsi.
Latics were playing some decent stuff in the opening stages, and they nearly fashioned an equaliser almost immediately.
Great footwork from Nick Powell saw Jack Collison play in Perch, whose powerful shot was well saved by Green.
McClean then showed quick feet to slip past Aaron Hughes, but his shot was saved at the near post when he might have been better advised going across goal.
The Irishman threatened again moments later but could only stab towards goal, with Green gathering at the second attempt.
Powell thought he was in for a shooting chance, but Nedum Onouha came flying in with a perfectly-timed challenge to snuff out the danger.
Rangers ended the half on top, but Morrison scuffed his shot straight at Al Habsi, who then saved easily from Nico Krancjar.
Looking at only a third defeat in 24 matches under Rosler, Latics came out for the second period with all guns blazing.
Perch’s cross was laid off by Powell to McArthur, who fired into the body of Green.
The ball rebounded back into McArthur and, unfortunately for Latics, just wide of the upright.
McClean then squandered a great chance to level, racing through the middle only to fire straight at the onrushing goalkeeper.
A nice ball from Josh McEachran found Collison, whose effort was blocked for a Wigan corner.
The resulting set-piece from McEachran was a beauty, and Ramis’ looping header came back off the bar.
QPR were hanging on at this stage, and they were bought a few moments when Joey Barton went down and required treatment from the trainer.
Whether intentional or not, it certainly appeared to work as Rangers stemmed the flow and lifted their game.
Bobby Zamora looked like he was through but turned inside at the last minute, offloading the ball to Benayoun, whose shot was blocked by Ramis.
Back came Latics, and Powell’s deflected shot was saved by Green, before Latics threw on Jean Beausejour and Jordi Gomez to try to spark a change in fortunes.
McClean led another break, only to be denied by a superb challenge by Clint Hill as he tried to shoot.
The home side nearly wrapped up the points when Ravel Morrison’s 25-yard free-kick beat Al Habsi but hit the bar, bouncing down on the line and away.
Zamora then missed his kick as he tried to net the rebound, with Perch clearing off the Latics line.
There was a bout of handbags between Ramis and Benayoun, who was booked for kicking the ball away as Latics tried to take a quick free-kick.
That silly booking came back to haunt the Israel ace in stoppage-time when he caught Gomez for a regulation second booking.
But Latics couldn’t make their one-man advantage pay, although substitute Nicky Maynard’s header did force a great save from Green right at the death.
Latics: Al Habsi; Rogne, Ramis, Kiernan; Perch, McArthur, McEachran, Collison, Crainey; McClean, Powell.
Subs: Carson, Caldwell, Gomez (for Rogne, 73), Beausejour (for Crainey, 60), Maynard, Fortune, Waghorn.
QPR: Greem; Onouha, Hill, Dunne, Hughes; Krancjar, Barton, Morrison, Carroll; Benayoun, Zamora.
Subs: Murophy, Simpson, Keane, Yun (for Morrison, 88), Henry (for Barton, 85), Hoilett, O’Neil.
Referee: S Hooper