Three goals in as many minutes for QPR ended Barnsley's resistance, keeping the West London club in the title chasing pack.
In a classic tale of two halves, QPR came out with a thunderous second-half performance to keep their unbeaten home record intact.
Martin Rowlands came closest to scoring in a disappointing first half, coming off the left wing and dancing inside to test Tykes keeper Sasa Ilic with a couple of rasping 25-yard efforts.
And it was Rowlands' pass that should've seen Kevin Gallen give Rangers the lead, but his right-foot volley was aimed straight at Ilic.
In the 60th minute Gallen did give QPR the lead with a smart turn and left-foot strike after Tony Thorpe had threaded the pass through.
A minute later it was two when Marc Bircham's 25-yard shot was parried by Ilic into Rowlands' path and the midfielder made no mistake.
The game was effectively sealed moments later when a lively Gareth Ainsworth nodded home Gino Padula's corner through a crowd of players.
With overexcited cries of 'Brazil!' coming from the stands, QPR continued to dominate a shell-shocked Barnsley side with some sparkling football.
And there was still time for Thorpe to get in on the act when he took the ball round Ilic and slotted home into the empty from a tight angle.
QPR boss Ian Holloway said: "I was very, very pleased to see my players grind it out this evening.
"On the balance of play in the second half I think we deserved it, and I was delighted with the link up play of the front two.
"It's difficult to break down a five-four-one but when you shut up shop and leak one, before you know it the game is over."