Blackburn boss Mark Hughes was left frustrated by poor refereeing and profligate strikers after seeing his side draw 0-0 at Crystal Palace.
"It was an innocuous challenge," he said of David Thompson's dismissal.
"The decision was made by the assistant referee and how he could see from where he was I don't really know.
"We had opportunities to score and possibly could have finished better, but credit to the goalkeeper - he was in the right place at the right time."
Thompson saw red late in the game after receiving his second yellow card, but Hughes conceded it had little bearing on the match.
He felt his team should have been out of sight by then instead of still desperately looking to break the deadlock.
"A little bit of control was lost by the officials and that was a shame as it was a decent game," Hughes added.
"It took a little bit of the edge off a good performance - our football was the best on show and we worked hard.
"We should have got more reward, certainly in the first half when we created three or four very good chances.
"We had more than enough to cause Palace a problem and we showed that.
"I can't fault the players, they showed a great work ethic. If they keep working hard I have no doubt we'll turn it round."