Before the game Rangers boss John Gregory had warned the club's supporters that they were in "serious trouble" in the league but he got the result at Loftus Road he wanted.
Gregory welcomed back Lee Cook to his starting line-up after the midfielder recovered from a rib injury.
And it was Cook who nearly opened the scoring in the third minute when his in-swinging corner forced Barnsley keeper Nick Colgan to make a hurried save.
Colgan was called into action three minutes later when Ray Jones wriggled free in the area. The striker's shot had plenty of pace but it was straight at Colgan, who saved smartly.
The Republic of Ireland stopper knew he was going to be in for a busy afternoon when Rowlands then tried his luck from 14 yards, forcing him to make a save at full-stretch.
But Rangers did not have to wait long to find a way past Colgan. Cook's surging run from the left wing was neatly finished off by Rowlands inside the box in the 15th minute.
The midfielder's sixth goal of the season brought an end to QPR's goal drought that had lasted 286 minutes.
The goal was what Rangers deserved as Barnsley's best chance came when a lofted ball into the box was cleared off the line by Marcus Bignot.
But going behind sparked the Tykes into life as they looked to claw their way back into the game. Leon Knight almost pulled them level in the 32nd minute when he raced clear of the Rangers defence.
However, he was first denied by an excellent recovery tackle by Damion Stewart, who then hacked Knight's second attempt clear to safety.
After the interval it was Rangers who resumed control of the game. Cook again was the main threat when he ran from midfield but he could not apply the finish.
Dexter Blackstock then missed two chances to put QPR further ahead. First he dragged his shot from the edge of the box wide of the post, and then he latched on to Cook's pass, but his blistering shot was well saved by Colgan.
Barnsley were again static in attack. Knight worked hard but was not picked out by his team-mates, while Daniel Nardiello looked to be on a different planet at times, aimlessly plodding around.
Ironically, the former Manchester United star could have pulled Barnsley level near the end but planted his shot straight at a defender.
Rangers' slump was ended, while Barnsley's caretaker manager Simon Davey certainly has his work cut out.