A late, late goal by Chris Maguire gave Sheffield Wednesday the points in the derby, after the Owls finished with 10 men and Barnsley with nine.
Stuart Gray wanted his team to show their authority on their own patch after an unbeaten run of nine games - and they were intent on doing just that, judging by the early stages.
They forced Barnsley back towards the Leppings Lane end and played four dangerous balls into the box in quick succession.
Llera narrowly failed to make contact with one of them, from Maguire, and a diving header by Afobe from a Lee pass was deflected for a corner by Ramage.
The first shot at goal came from O’Grady, who could have done better than side-foot to Kirkland after a through ball flicked off the top of Llera’s head, but the Owls bossed possession.
Nuhiu put his team in trouble by ignoring the ball, strangely, just outside his own box: Hunt weaved towards goal, a chance beckoned and his effort was turned for a corner.
That began a torrid couple of minutes for Wednesday: Semedo blocked a great strike from Proschwitz, the striker fired it back towards goal, and Kirkland saved, in the 18th minute.
From the ensuing corner, Nuhiu failed to pick up Ramage, and the defender’s goalbound header was nodded over the bar by Llera.
Nuhiu headed a half-chance yards wide from a good ball by Maguire, Back came the Owls, with Lee, Maguire and Afobe all showing confidence and quality on the ball.
Maghoma angled a first-class ball towards the far post where Llera was not quite quick enough to make contact as he lunged in unmarked.
Afobe was making an impressive debut, wanting to try things on the ball and passing well, but it became an awful debut for his Arsenal colleague, Frimpong, when he was sent off in the 31st minute.
Booked earlier, the midfielder chopped down Maguire near the corner flag and received a second yellow card, followed by red.
Three minutes later it was a sad day too for O’Grady on his return to Hillsborough. He was sacrificed by Danny Wilson, with Dawson sent on to replace Frimpong in midfield, and Proschwitz left up front on his own.
The home crowd sportingly applauded O’Grady from three sides of the ground, a gesture clearly appreciated by the striker as he walked off.
Wednesday pressed the 10 men back but lacked a bit of composure and precision in their keenness to score, and the Reds pulled men behind the ball, also escaping when Nuhiu headed over the top from a Maguire cross.
Indeed it took a good save by Kirkland from Jennings on a breakaway in the third and final minute of stoppage time to prevent Barnsley from taking a shock lead.
Palmer showed one way to break down the Reds’ stubborn resistance when he surged down the line to play a ball into the box. Maguire was challenged by Mellis and went down but was booked for diving for the second time in a fortnight. Hunt suffered the same fate after he ran at Llera in a counter-attack.
Barnsley were well organised, in their two banks of four, and almost inviting Wednesday to try to find a way through them.
Gray took off Nuhiu and turned to the pace and energy of Lavery to accompany Afobe who was having less of an impact in this half and was perhaps tiring in his first senior game since last March. He was taken off in the 70th minute; Jermaine Johnson came on, to the right wing, and Maguire went up front. The ref evened the numbers by sending off Johnson in the 80th minute in what, at first sight, seemed a harsh decision. Shea was down and hurt by the winger’s challenge, and the resulting red card was the Owls’ third in three games, with JJ joining Coke in qualifying for a three-match ban.
Maguire was given more of a right-flank role, with Lavery down the middle.
The Owls stayed on top, but the Reds might have had a penalty after Melis took on Llera. Probably frustrated by that, Melis moments later hacked down Maghoma and was given an instant red card in the first of five added minutes.
But it was actually just into the seventh minute of added time when MAGUIRE slammed a shot into Steele’s bottom right-hand corner from around 20 yards. Home players, fans and the bench went wild.