ALBION'S miserable 61-year run without a win on Tykes soil continued as they tumbled to a second consecutive 2-1 away defeat.
Stourbridge-born Daniel Nardiello punished Bostjan Cesar's mistake on the half-hour mark to put the hosts ahead.
And Simon Davey's men deservedly doubled their lead before the break thanks to Jon Macken's strike in the third minute of stoppage time.
The Baggies stepped up a gear in the second half and got back in the game thanks to James Morrison's fourth goal of the season in the 58th minute.
Kevin Phillips and substitute Zoltan Gera both missed glorious opportunities to pinch a point.
And, try as they might, Tony Mowbray's troops could not find a leveller to give the Baggies' near 4,000 travelling support - half ferried on 40 free coaches laid on by the club - something to take back down the M1.
Chris Brunt and Filipe Teixeira were restored to the Baggies' starting XI on the flanks, while Zoltan Gera dropped to the bench.
Morrison shuffled inside to partner Jonathan Greening in the middle of the park after Robert Koren missed out altogether with a calf injury.
Barnsley made a bright start and saw Anderson De Silva pounce on a clearance from a corner and drill in a 20-yard strike in the second minute.
The Brazilian's effort cannoned off Macken in the penalty area and presented Nardiello with a glorious chance, which he fired against the inside of the right-hand post and the ball flew to safety.
Just three minutes later, a clash of heads between Cesar and Carl Hoefkens gave Macken a clear sight of goal.
But the former Manchester City hitman dragged his effort wide of the right-hand upright under pressure from the advancing Dean Kiely.
In the seventh minute, Brian Howard pumped a long free-kick into the box which Martin Albrechtsen was forced to head just over his own goal with Stephen Foster breathing down his neck.
Three minutes later, Kiely had to show good handling in a bumpy penalty area to grasp Rob Kozluk's 25-yard drive.
Albion finally threatened when Albrechtsen powered in on Brunt's left-wing corner in the 16th minute but saw his goalbound header inadvertently blocked by Phillips.
A minute later, Nardiello fluffed another great chance after Cesar failed to cut out Martin Devaney's right-wing cross.
The Baggies needed Paul Robinson to make a vital headed interception in the 21st minute to prevent Nardiello getting on the end of Diego Leon's left-wing cross.
A Barnsley goal had been coming and Albion gift-wrapped them one on the half-hour mark.
Cesar dallied too long on the ball just inside his own half, allowing Nardiello to pick his pocket and drive forward before slotting coolly past Kiely.
Albion regrouped but struggled to get any change out of the Tykes' defence.
Things went from bad to worse in the third minute of stoppage time when Nardiello saw his shot from Howard's near-post free-kick blocked on the line by Greening.
It was only a temporary reprieve as Macken squeezed home the rebound from ten yards.
Mowbray made a double change at the break as Cesar and the injured Roman Bednar made way for Leon Barnett and Craig Beattie.
Teixeira, who had been Albion's brightest player, recorded the first shot of the second half when he cut inside from the left and drilled the ball straight at Tony Warner.
But the visitors left themselves exposed at the back from their own corner in the 49th minute and Warner's quick throw out set Nardiello in on goal.
The Tykes hotshot, under pressure from Brunt, could only fire into the side-netting from 12 yards.
Morrison controlled Teixeira's pass in the 54th minute and shifted the ball to his right foot before forcing Warner to make a sprawling save low to his left.
Just two minutes later, the former Liverpool keeper was in the action again as he bravely blocked at Barnett's feet on the edge of the six-yard box after he'd been found by Robinson.
The Baggies pulled a goal back in the 58th minute. Morrison drove into the penalty area to find Phillips who back-heeled the ball back to the former Midddlesbrough ace and he poked home from eight yards.
But Barnsley still looked dangerous on the break and, a minute later, Nardiello's strike deflected off Barnett, past the wrong-footed Kiely and just wide of the right-hand post.
Kiely then had to pull off a terrific save to beat out Howard's swerving shot in the 62nd minute.
Two minutes later, Mowbray made his final change as Gera came on for Brunt.
Beattie did well to spin Dennis Souza and power to the edge of the area in the 67th minute before teeing up Phillips, who scuffed his left-foot shot straight at Warner.
Seconds later, a swift Baggies break saw Morrison present Gera with a golden opportunity which he screwed wide of the left-hand post from 15 yards.
Simon Davey made a change in the 72nd minute as he brought on Michael Coulson for Nardiello.
Albion enjoyed plenty of possession during the dying stages but failed to trouble Warner again as the Oakwell men held out for all three points.
BARNSLEY (4-4-2): Warner; Foster, Souza, Nyatanga, Kozluk; Devaney, Howard, De Silva, Leon (Hassell 84); Nardiello (Coulson 72), Macken (Ferenczi 80). Subs not used: Odejayi, Campbell-Ryce.
ALBION (4-4-2): Kiely; Hoefkens, Albrechtsen, Cesar (Barnett HT), Robinson; Teixeira, Morrison, Greening, Brunt (Gera 64); Bednar (Beattie HT), Phillips. Subs not used: Danek (gk), Pele.
GOALS: BARNSLEY - Nardiello (30), Macken (45+3). ALBION - Morrison (58).
BOOKINGS: ALBION - Cesar (foul 14), Greening (foul 83).
REFEREE: T Bates (Staffordshire).
ATTENDANCE: 13,083.
ALBION STARMAN: Filipe Teixeira.
PIC: OAKWELL WOE...Bednar battles with Souza
