The Reds are dealt a hammer blow as Albion take all three points in a game of two halves.
Barnsley fell to defeat at Oakwell in new Head Coach José Morais' first match in the hotseat.
First half stunners from Jamie Allen and Jacob Davenport gave the Brewers a half time lead with Barnsley failing to produce anything of note in a torrid opening period.
Dani Pinillos' deflected strike gave the Reds hope in the second half, but despite incessant pressure and roared on by the home crowd, it wasn't to be for Barnsley and the winless run continues with Burton now leapfrogging the Reds in the relegation zone.
Morais had kept an unchanged side following the 1-1 draw with Sheffield Wednesday last time out, with Brad Potts, Dimitri Cavaré and Adam Jackson returning to the subs bench after spells out.
With many spectators just getting to their seats, the visitors struck an early blow, as Allen rocketed an effort into the roof of the net from all of 25 yards.
That goal rocked the Reds and they struggled to break down a stubborn and direct Albion side for the remainder of the half, a long range Joe Williams effort the only real shot of note, with Burton the more likely to add another goal despite being camped in their own half.
A superb Andy Yiadom block prevented the Brewers from making it two as we edged towards the break, before right on the stroke of half time, referee Robinson awarded the away side a dubious free kick on the edge of the box, which Davenport curled home into the top corner for 2-0.
The Reds left the pitch at half time to jeers after what had been a sloppy and unimaginative showing in the first 45.
HALF TIME: Barnsley 0-2 Burton
Mamadou Thiam had warmed up vigorously throughout half time, and he replaced Lloyd Isgrove as the game restarted with Barnsley now attacking the Ponty End.
Kyle MacFadzean's blatant handball saw him enter the book as Tom Bradshaw looked to be through on goal and minutes later Lucas Akins cleared off the line as Morais' men turned up the pressure.
Brad Potts replaced Adam Hammill on the hour mark, and he played a huge part in turning the tide.
62 minutes in and Bradshaw was hauled down through on goal, but again the referee only deemed it worthy of a yellow to Tom Naylor. The resultant free kick by Gary Gardner looked to be heading in but 'keeper Stephen Bywater grabbed hold right on the line.
Next chance fell to Oli McBurnie whose shot was cleared off the line after great work by Gardner out wide.
On 70 minutes, McBurnie's header from Thiam's corner hit the bar and somehow Matt Mills' follow-up header went over from a yard out!
Kieffer Moore was sent on for Bradshaw just afterwards.
McBurnie was hacked down by Akins, and he entered the book. From the free kick, the ball fell to Dani Pinillos and his vicious strike deflected in off a crowd of bodies to give Barnsley hope.
On 89 minutes, Pinillos curled a sweet effort just wide of the post.
It had been all Barnsley in the second half and in the last minute of injury time everyone thought a point had been earned.
As Potts charged through, he was clearly checked by MacFadzean in the box, the loose ball fell to Thiam who slotted home to send Oakwell wild.
Sadly, the referee blew up, which at first we thought might have been for a penalty, but it looks to have been given as offside. Cruel, cruel luck.
But it's another bad result on the face of it and the Reds need to rally quickly in time for the Saturday trip to Birmingham City.
FULL TIME: Barnsley 1-2 Burton
Townsend; Yiadom, Mills, Lindsay, Pinillos; Gardner, Williams, Hammill (Potts 58), Isgrove (Thiam 46); Bradshaw (Moore 70), McBurnie.