Both sides displayed attacking prowess and the hosts had chances to restore parity through Jason Shackell and Jacob Butterfield.
Referee Anthony Bates resisted heavy pressure from both sets of fans to dismiss both Taarabt and Butterfield after a bad-tempered clash between the pair in the first half.
Rangers now go into their next npower Championship game aware that their 16-year absence from the top flight could be over after just 90 more minutes.
Even then QPR could face a points deduction with the Football Association due to rule over charges regarding the ownership of Argentinian midfielder Alejandro Faurlin so even a win next time out against Derby might not result in them going up.
Talismanic home captain Shackell was fit again after illness and visiting manager Neil Warnock made four changes after the heavy defeat at Scunthorpe; the most significant being the reintroduction of playmaker Taarabt.
The R's found the back of the net after 47 seconds, returning captain Taarabt tricking the Barnsley defence with a step-over and blasting beyond Luke Steele.
The Tykes were denied four minutes later when Danny Haynes' powerful shot deflected off Paddy Kenny only for Andy Gray to blast against the former Sheffield United goalkeeper.
On 32 minutes, Bradley Orr bravely headed clear when Marlon Harewood found himself in an excellent position to score.
Both sides were lucky to end the first period with 10 men, Taarabt fouling Butterfield and receiving a yellow card, only for the Barnsley man to retaliate shortly afterwards and pick up a booking for his troubles.
Mark Robins' men might have gone in level at the break, Shackell failing to convert a header following Butterfield's cross as half-time approached.
With just over 11,000 at Oakwell, both sets of fans were in full voice as their sides emerged for the second half. The visitors cheered as Tommy Smith tapped in from close range on 55 minutes, but the goal was ruled out for offside.
The home fans were on the edge of their seats when Kaspars Gorkss conceded a free-kick after a foul on Gray. Kieran Trippier whipped in a dangerous ball but Kenny was on hand to smother.
Just before the hour mark, Haynes tested Kenny again but the Republic of Ireland international stood firm to save.
Taarabt made way for Hogan Ephraim as the game entered the final 20 minutes. The Hoops may have considered the tie won but Butterfield skimmed the post on 70 minutes to set up a tense finale.
Heidar Helguson bustled into the box after 82 minutes to connect with Wayne Routledge's cross but managed to clip his header agonisingly past the left post.
Butterfield provided a late scare for the R's with five minutes remaining, his long-range effort rattling Kenny's post but Warnock's men return to London already dreaming about next season's away days.
Barnsley 0-1 QPR: Match Report - view commentary, squad, and statictics of the game as it happened.