Barnsley were stunned in stoppage-time against Shrewsbury at Oakwell as Jordan Clark, a former Oakwell youngster, fired home the winner in the 93rd minute.
Clark fired home from 15 yards via a deflection as the visitors - and their ex-Reds boss Micky Mellon - secured their first League One win of the season in dramatic fashion.
Barnsley got themselves off to the worst possible start at a sun-drenched stadium.
The hosts fell behind after just seven minutes courtesy of a scruffy goal as Mark Ellis bundled home a corner-kick from former Red Liam Lawrence via unfortunate goalkeeper Adam Davies.
However, Barnsley dominated the remainder of the first period and were back on terms by half-time.
Josh Scowen teed up Conor Hourihane who struck a post from 20 yards, while from closer in, Marley Watkins side-footed against the opposite post.
Seven minutes before the interval Lee Johnson’s man grabbed their well-deserved leveller.
Watkins expertly played in strike partner Sam Winnall, and he drilled home clinically from the edge of the box, giving goalkeeper Jayson Leutwiler no chance.
The first chance of the second period fell to Shrewsbury, with Clark seeing a well-struck effort tipped round the post by the agile Davies.
Junior Brown then found space in the Reds’ box before whipping in a shot which missed the upright by a whisker.
It was the 62nd minute before the Reds carved out a second-half opportunity, with skipper Alfie Mawson heading over as he rose to meet a long throw-in from Marc Roberts.
Winnall headed over the top as the hosts pressed in the latter stages, while at the other end Davies saved superbly from Jean-Louis Akpa-Akpro before Clark pounced so late on.
Barnsley (4-4-1-1): Davies; Wabara, Roberts, Mawson, Nyatanga; Scowen, Hourihane, Pearson, Crowley; Watkins; Winnall.Subs: Townsend, Rothwell, Smith, Bree, Jackson, Smith, Harris.
Shrewsbury (3-5-2): Leutwiler; Ellis, Knight-Percival, Grandison; Lawrence, Ogogo, Wesolowski, Clark, Brown; Barnett, Tootle. Subs: Halstead, Cole, Akpa-Akpro, Collins, Whalley, McAlinden, Sadler.
Referee: Stuart Attwell (Nuneaton).