Reds boss Danny Wilson expressed his disappointment after his side picked up only a point against Brighton at Oakwell.
Barnsley had two great chances to win the match, but had to settle for a point with 10 men following Kelvin Etuhu's 76th-minute red card.
"The disappointment of the sending off late in the game, took away our chances of winning the game.
"The second booking is right - there's a clip, but the first one is nonsensical in my eyes.
"It's a shoulder charge. He's come away with the ball, cleanly, he's just too strong for the boy. It's not even a foul.
"We've played very well at times against a quality side.
"The crowd were in great voice for us, all the game. They would have really pushed us on towards the end. They were as stunned as we were for the decision.
"Kelvin's been a revelation since he's come in at right back. Today we saw against the quality he played against - they didn't get a kick all game, that's three on the spin.
"I'm so dispapointed for him because he was my man of the match."
Ryan McLaughlin went close with a header that struck the bar, as did Jean-Yves M'voto whose header flashed past the post.
"We've played three very difficult teams for different reasons and come away with a very good return," added Wilson. "We thought we could get maximum points today."