Paul Heckingbottom's side are denied a deserved point at Molineux as Wolves strike late for all three points.
A 94th minute winner from Alfred N'Diaye snatched all three points for Wolves here at Molineux.
Just two minutes earlier the Reds had deservedly levelled the game up when Adam Jackson fired home through a crowd.
Wolves had taken the lead midway through the second half when Bright Enobakhare stuck home a majestic volley from just inside the box.
Hecky had reverted back to the same starting XI who appeared in the last Championship outing against Aston Villa, with the likes of Angus MacDonald and Ryan Hedges having to settle for a place on the bench.
It was a very even first half, very few opportunities were created by either side, but both were looking to force the issue once in possession.
Jota put a header over the bar on 14 minutes for Wolves, before Tom Bradshaw saw a header well saved following a terrific Brad Potts cross.
Ivan Cavaleiro was proving a handful on the right, cutting in on his left foot. He saw a fierce drive flash just over the crossbar.
Then came a huge talking point, right on the half hour mark.
Bradshaw was clearly pushed inside the six-yard box, but to everyone's amazement, referee Simpson ignored the appeals for a penalty.
The half finished with the impressive Potts linking with Adam Hammill who curled an effort towards goal from the edge of the box only to see John Ruddy grasp the ball at the last minute.
HALF TIME: Wolves 0-0 Barnsley
Wolves replaced left back Vinagre who'd been terrorised by Hammill, with Barry Douglas at half time.
Adam Davies - making his 100th consecutive appearance - denied Douglas at the near post on 52 minutes as the home side started brightly.
Harvey Barnes saw an effort inside the box blocked as it was heading for goal.
Jackson made a superb last-ditch tackle to thwart Leo Bonatini who would have been through on goal.
Caveleiro was then replaced by Enobakhare, and on came Ryan Hedges in place of Barnes as both sides searched for a goal.
Jota slid through a great ball which Bonatini fired wide as Wolves threatened.
Hedges was played in by Potts but his shot on goal was deflected just wide for a corner. It was end to end stuff.
But then came the best moment of the game in terms of quality, as Enobakhare steered home a cross on the volley, it was a spectacular finish to give Wolves the lead with just 10 minutes left to play.
Hecky threw on Cameron McGeehan and Ike Ugbo in place of Potts and George Moncur, a last roll of the dice...
And on 92 minutes Barnsley equalised dramatically..
A free-kick was swung in by Hammill, nodded back across goal by Liam Lindsay and after a scramble, there was the imperious Jackson to rifle home into the roof of the Wolves net to make it 1-1 with only a minute remaining of added time.
However, the hosts broke Barnsley hearts in the very last minute as substitute N'Diaye found too much room in the six yard box before firing beyond the blameless Davies to get the victory.
FULL TIME: Wolves 2-1 Barnsley
Reds XI: Davies(GK); McCarthy, Jackson, Lindsay, Pearson; Williams, Moncur (McGeehan '81), Potts (Ugbo '82); Hammill, Bradshaw, Barnes (Hedges '71).
Unused: Townsend(GK), Pinnock, MacDonald, Thiam.