QPR hung on for a precious win despite a second-half revival from Barnsley.
For all that, the Yorkshiremen failed to bring a single save from Rangers keeper Nick Culkin even though there was five minutes of extra time in which to rescue a point.
Barnsley were struggling when Richard Pacquette struck in the 11th minute.
Richard Langley had two attempts at crossing from the left, and his second effort was headed back across the face of goal for Pacquette to hook home from six yards.
The Tykes could have gone further behind when Kevin Gallen took Pacquette's measured cross in stride, only to see his goalbound shot blocked by Steve Hayward.
As half time approached a back pass from Brian Oo'Callaghan looked harmless, but Andy Marriott's sloppy control almost let in the rampant Pacquette, but the two collided and the ball spun off for a corner.
Rangers were rocked when Matthew Rose was stretchered off in injury time after twisting his knee.
Straight after, a half-chance fell to Kevin Donovan on the edge of the box and his right-foot shot thumped the underside of the bar only to bounce out to safety.
Buoyed by this rare attack Gino Padula came to Rangers' rescue in exactly the same way as Hayward had done for Barnsley.
The Rangers defender came across to block Kevin Betsy's shot after the striker had latched on to a ball played beyond the defence.
On the hour a dreadful challenge from Gary Jones on Padula threatened to add to Rangers' injury woes, but the defender eventually got to his feet and Jones escaped with just a yellow card.
Chris Morgan then saw a flashing header drift over the bar as he met a corner and Barnsley looked as if they were good for a point.
However, despite conceding three corners in extra time, Rangers held on to strengthen their position in the play-offs.