Barnsley's Sky Bet Championship play-off charge continued as they beat QPR 3-1 to make it six wins in a row.
Charlie Austin's equaliser cancelled out Daryl Dike's opener but Alex Mowatt's free-kick and Carlton Morris' second-half goal gave the visitors the points.
Barnsley are now unbeaten in eight matches, while back-to-back defeats is a major blow for Rangers, whose recent four-game winning run raised hopes that they might yet challenge for the play-offs.
Dike put the Tykes ahead by holding off Lee Wallace to head in Mowatt's 23rd-minute corner at the near post - the American striker's second goal since signing on loan from Orlando City at the start of last month.
Rangers hit back four minutes later with Austin's fifth goal in 10 appearances since his return for a second spell at the club.
Ilias Chair's lofted free-kick reached Yoann Barbet, whose left-footed volley was parried by keeper Brad Collins to Austin and the on-loan West Brom striker finished emphatically.
But Barnsley quickly regained the lead with a fabulous goal from Mowatt, who clipped his 25-yard free-kick beyond keeper Seny Dieng and into the top corner of the net.
And Morris doubled that lead 12 minutes into the second half, straight after coming on as a substitute.
Morris, a January signing from MK Dons, latched onto Mowatt's ball over the top and raced away from QPR captain Geoff Cameron before slotting home his third goal in six games.
Rangers were well beaten but the result might have been very different had Austin or Lyndon Dykes been able to take early chances when the match was goalless.
Austin fired inches over after being found by Stefan Johansen's excellent pass and the stretching Dykes was just unable to put away Todd Kane's low cross from the right.
It continued a frustrating first season in west London for Scotland striker Dykes, who has scored just once from open play since his summer move from Livingston.
QPR struggled to create clear-cut chances in the second half and never looked like pulling off a comeback after Morris' goal.
And their poor defending for two of the goals they conceded will frustrate boss Mark Warburton.
Mowatt's strike was a beauty but Rangers' failure to deal with a set-piece led to the first goal and a routine long ball caught them out for the third.
What the managers said...
QPR's Mark Warburton: "Barnsley are very good at what they do. They're direct, commit bodies forward and take risks at the back. We had to time our runs and not play to their strengths. In the first 10 minutes we did that and created a couple of great chances. We've got to get our rewards.
"At 2-1 down we've got to be patient, make sure we impose ourselves on the game and don't play to their strengths. To then give away a goal like that - we're attacking down the left and then don't get into shape - is criminal.
"We've got to be better in front of goal. If you give away set-pieces and don't take your own rewards, you pay the price. If you score the goal it changes the game because the opponent then has to come out and attack and we'd have space and are a team that likes to move the ball."
Barnsley's Valerien Ismael: "We were feeling some tiredness in the second half and that's why we made the change with the front three. It was always my thinking to do this when we have five substitutes. We have the possibilities. It was a lucky moment for us because it changed the game. We then scored with our first chance and after that it was about managing the game."
"It's a reward for the hard work the players put into games and for the staff and background people who are very involved. It's about teamwork. But the job is not done. The season is not finished as 13 games remain and we have to stay focused. We want to keep moving in the table but the most important thing is to stay focused on the next game. We'll see what our position is at the next international break, but at the moment it doesn't matter."