Johann van Graan spoke through gritted teeth as he called for "consistency" from the officials in the aftermath of Munster's eight-point loss to Leinster.
The head coach pin-pointed a crucial call that went in favour of the hosts just after the break.
The ball broke loose after a tackle by Sammy Arnold and winger Keith Earls raced from his own 22 to dot down.
However, referee Ben Whitehouse, alerted by a touch judge, called a deliberate knock on. James Lowe scored soon after and Leinster had a 13-point cushion.
"I think it was a 14-point swing," said Van Graan.
"We got called back for a certain try. There was a call made, [Leinster] went to the corner and then they scored a try. I guess all I can say is that you want consistency."
It was arguably a call that decided the match and cost Munster a shot at a first win over their rivals since December 2016 but Van Graan did admit to being encouraged from scoring three tries against the European champions in Dublin.
"We had asked for a big performance and I'm very proud of my team," he said.
"I thought we did that tonight. We came back against a team that has not lost here since 2015, I believe. I thought we were right in it with those three or four scrums on their goal-line, getting penalty after penalty.
"We got away with a try. It would have been great to get away with something else. [I'm] very proud of my team. I thought we really stuck to our guns.
"The two teams went at each other for 80 minutes and unfortunately certain calls went against our team"
"All credit to Pete [O'Mahony] and the leadership [group] on the pitch tonight. We stayed calm and I thought we played some brilliant rugby out there tonight.
"We want to improve as a team and I thought we did that. Unfortunately, we came against a team that are possibly one of the best sides in the world.
"All credit to them and I thought some of their individuals were fantastic. Someone like James Lowe had a fantastic game.
"I think you've got to first give credit to the opposition.
"We got beaten by the better team today, unfortunately. Tonight was a great occasion for Irish rugby.
"The two teams went at each other for 80 minutes and unfortunately certain calls went against our team.
"That being said, with five minutes to go we conceded another penalty that took the game away from us; made it eight points and impossible for us to get back into the game."