A second-half penalty from sub Conor Hourihane handed Barnsley their first victory of the season as Burton were sunk at Oakwell.
Hourihane slotted home after the impressive Josh Scowen had been tripped in the box by Brewers’ defender Damien McCrory.
The first half ended goalless at Oakwell, but it had been Burton who had missed the clearer-cut chances.
Joe Rothwell went close for the Reds early on and the lively Josh Scowen fizzed a 25-yard drive narrowly over the top, but the Brewers bossed proceeding in the run-up to the break.
Dutch front-man Abdenasser El Khayati was the tormentor-in-chief, forcing the recalled Adam Davies into a superb one-handed save.
El Khayati then teed up Stuart Beavon, who again forced Davies into a smart, low stop.
Lucas Akins ought to have done better for Jimmy Floyd Hasselbaink’s men just before the break, but he screwed a low effort woefully wide from just 12 yards out.
The visitors continued to dictate the pace at the beginning of the second half.
They almost went in front in the 58th minute when defender Phil Edwards rose well to meet Mark Duffy’s corner, only to head over the top.
The Reds bounced back, however, with substitute Hourihane looking to make an immediate impact.
Barely two minutes after coming on he stung ‘keeper Jon McLaughlin’s palms with a brilliantly-hit shot from the edge of the box.
After Hourihane had broken the deadlock, Burton sub Timmy Thiele came closest to levelling as his shot crashed against the crossbar late on.
Barnsley (5-3-2): Davies; Bree, Roberts, Nyatanga, Mawson, Smith; Pearson, Rothwell, Scowen; Winnall, Watkins. Subs: Townsend, Hourihane, Wilkinson, Crowley, R Williams, G Williams, Digby.
Burton (4-4-2): McLaughlin; Edwards, Cansdell-Sherriff, Mousinho, McCrory; Akins, Weir, Naylor, Duffy; El Khayati, Beavon. Subs: Matthews, Reilly, Butcher, O’Connor, Thiele, Binnom-Williams, Palmer.
Referee: Jeremy Simpson (Lancashire).