Story of the match
In a first 15 minutes that was played at an extremely fast pace, it was the hosts who created the first opportunity, when Charlie Austin latched onto Stefan Johansen's perfectly-weighted through ball.
Five minutes later, Lyndon Dykes should have opened the scoring for the R's but the summer signing was unable to convert from Todd Kane's low-cross.
Despite the home side's early few chances, the visitors looked dangerous throughout the first half and created their first meaningful opportunity in the 22nd minute, when Romal Palmer's first time effort troubled Semy Dieng in the Rangers goal.
Barnsley's January signing Daryl Dike nodded the visitors into the lead from the resulting corner, beating the QPR goalkeeper to the ball from Alex Mowatt's set-piece.
Parity was restored just four minutes later, when Austin netted his fifth goal since joining the R's in January, reacting quickest to Yoann Barbet's volleyed effort.
Mowatt regained the visitors' advantage just two minutes later, curling a free-kick into the top corner in spectacular fashion from a central position 20 yards out from goal.
In the 37th minute, Geoff Cameron nearly added an equaliser for the hosts, heading onto the post from Ilias Chair's free-kick.
The start of the second half did not follow the same 100 mile an hour nature of the first, with both sides unable to threaten in the final third.
Second half substitute Carlton Morris doubled his side's advantage in his first involvement just two minutes after coming on. The former Norwich City man latched onto a through ball in behind with his first touch setting up for a composed finish in the 57th minute.
In the 78th minute, Austin nearly added his second of the day, capitalising on Collins' mispunch but he was unable to steer his effort caway from Michal Helik on the line.
The three points for the visitors takes them into the play-offs for the first time this season – an exceptional achievement for the club who were without a win in their first seven games of the season. The Tykes may not be favourites to retain their position within the top six, but if they keep performing putting in performances like the one against QPR, it will be no surprise to see them claim a play-off spot come May.
After picking up 19 points in eight games, the R’s have come crashing back down to reality with a second successive defeat. The gap between QPR and Rotherham United in 22nd has been cut to a mere eight points, a big blow to the West London club.
On a day where QPR lacked in the final third, Stefan Johansen remained his tough- tackling self. He won possession for his side well and progressed forward with the ball well when the opportunity was presented.
Assisting the first and scoring the second, it was a successful day for Barnsley's Alex Mowatt. The central midfielder enjoyed dominating the middle third and kept things simple, whilst working extremely hard for his team.