QPR manager Neil Warnock was left fuming by the performance of referee Lee Probert after what he described as a "cruel" decision.
Warnock was angry that Danny Graham was not punished for handball leading up to Swansea's opener in the 1-1 draw
"The referee saw it was handball but said it was not intentional," said Warnock. "It was a kick in the teeth.
"It was a crucial decision. It felt such an injustice at half-time but it spurred us on."
He added: "It's the big decisions that you want referees to get right.
"I thought there were a number of mistakes tonight but it's the match-winning ones you want them to get right. You've got to know the game.
"If he [Graham] doesn't handle it and control it to shoot then it goes over Luke Young's head and we clear it."
Jamie Mackie pulled a goal back to earn Rangers a point, but that was not enough to satisfy Warnock.
"I'm disappointed that we haven't got three points," he added. "I feel we should have got three points; we played very well today."
Asked what he thought of Probert's display, Warnock replied: "He was consistent right from the first minute to the last."
Swansea boss Brendan Rodgers was equally scathing of Probert, who waved away a penalty appeal when Graham appeared to be fouled by Armand Traore.
"It was a clear penalty," Rodgers said. "I have had the chance to see it from a few angles and it was a definite penalty.
"Normally with the referee so close that's a penalty. I thought it summed up Lee's performance, which was interesting to say the least."
Warnock added: "I said to Brendan, 'I hope it's the most obvious penalty that you've ever had not given', and we just had a laugh, both of us."