Reds 0 (Frimpong sent off 31, Mellis sent off 90)
Barnsley were undone by virtually the last kick of the game with a sickening late goal in a match that saw two Barnsley players see Red.
The hosts came out of the traps the quicker of the two sides and immediately utilised their physique with deep crosses into the Barnsley box.
O'Grady nipped in behind the Wednesday defence on eight minutes but his shot lacked the power to beat Kirkland from inside the left-hand channel of the area.
After Mellis was denied a free-kick on the edge of the box, Hunt reacted quickly to dance his way into the area but was blocked from a clear shot at goal.
Unbelievably the Reds were denied the lead when a corner found Proschwitz unmarked, his vicious volley was blocked on the line and he latched onto the rebound only for Kirkland to turn over for a corner on 18 minutes.
With 22 gone Wednesday responded with another deep cross from Maguire for the big man Nuhiu but he planted his header six yards wide.
The Reds were dealt a massive blow as Emmanuel Frimpong was shown his marching orders for a second bookable offence on 31 minutes. It was now a mammoth task for the Reds.
Chris O'Grady was sacrificed for midfielder Stephen Dawson on 34 minutes. Three minutes of stoppage time was added as the Reds looked to hang on before the break.
Despite Wednesday having the advantage in numbers, Barnsley pulled out the next best chance as Jennings raced onto Brek Shea's through-ball and fired at goal from 20 yards - forcing Kirkland to palm wide.
The Reds were standing firm and Wednesday were offering little going forward and looked to be in no particular rush on the ball.
Luke Steele had to tip a deflected header over the bar on 62 minutes from Onyewu. From the resulting corner Kennedy cleared the delivery onto his own post before the first change of the match.
Caolan Lavery replaced Atdhe Nuhiu on 63 minutes.
Steele had to adjust himself to make another smart save on 68 minutes as Lee's shot deflected towards goal. The chance came as the Reds were just trying to be too cute in clearing the ball.
Jermaine Johnson came on for the Owls - replacing Benik Afobe on 70 minutes.
The Reds made a second change as Dale Jennings came off for Jim O'Brien with 18 left on the clock.
On 76 minutes Jack Hunt pulled up with cramp after a fine debut and was replaced by Tomasz Cywka - meaning Jim O'Brien moved to right-back.
Jermaine Johnson was shown a straight red on 80 minutes for a high foot on Brek Shea which left the U.S.A international on the deck in a heap.
Maguire whipped in a vicious free-kick from the left that took a nick on its way over and just flashed wide of the far post.
Five minutes of stoppage time was added and the Reds were going to play out the match with nine men as Jacob Mellis lunged at Jacques Maghoma.
Barnsley could have even gone to pinch a winner has Proschwtiz managed to get a shot away on the turn from Kennedy's quick free-kick.
Jeremy Helan replaced Helan with seconds remaining as the Owls pumped in a free-kick. It was an absolutely sickening last kick of the game as Chris Maguire picked up Jim O'Brien poor clearance and hammered into the corner from 20 yards seven minutes into stoppage time. The Reds were so unfortunate considering Steele had barely been troubled all game.
Sheff Wed: Kirkland, Palmer, Onyewu (Helan 90), Llera, Mattock, Maguire, Lee, Semedo, Maghoma, Afobe (J. Johnson 70), Nuhiu (Lavery 63).
Subs: Martinez, Corry, McCabe, McPhail.
Reds: Steele, Hunt, Kennedy, Cranie, Ramage, O'Grady (Dawson 43), Proschwitz, Shea, Jennings (O'Brien 72), Mellis (sent off 90), Frimpong (sent off 31).
Subs: Turner, Lawrence, Cywka, McCourt, M'voto.
Referee: Andre Mariner.