Northampton Saints lock Christian Day hit out at supporters who abused referee Matthew Carley following the 19-19 draw at Bath.
England's Courtney Lawes was initially judged to have put in an off-the-ball hit on George Ford, but after consultation with the TMO a penalty was not awarded to Bath and the game finished with the scores level.
Bath fans were left upset by the decision and according to Day gave Carley some "shocking" abuse, with Day underlining that such behaviour doesn't belong in the sport.
"Walked off next to the ref at the end and the abuse he got was shocking. Don't care if he got it right or wrong. Doesn't belong in rugby," tweeted Day.
Northampton boss Jim Mallinder refused to criticise the referee for any decision made throughout the match, saying it was a job that he couldn't do.
"I think the result was probably just about fair. I'm not going to criticise the referee. It's a difficult job, isn't it - I couldn't do it," said Mallinder.
"Bath have got a big, heavy scrum there, with two international props. They defend well and they've got exciting runners out wide - and George Ford makes them tick. But we know we're a good side as well, ball in hand.
"It was a close contest and when we play them again in the Amlin Cup final it's going to be equally as close.
"I was a little bit disappointed with some of our play, to be honest. We put ourselves under pressure getting out of our half. We weren't as accurate as we should have been.
"We should have kicked the ball off the field but we didn't, and gave them opportunities to counter-attack.
"We defended very well generally but we gave them two or three easy kicks at goal. In the big games, we need to improve."