Wasps boss Ian McGeechan was full of praise for Munster following their 19-3 victory in Ireland on Saturday, but he questioned referee Nigel Owens's decision to sin-bin Simon Shaw for not retreating the required ten yards at a penalty.
The loss means that Wasps are now out of the Heineken Cup, with the defence of their title being washed away in treacherous conditions at Thomond Park.
Munster fly-half Ronan O'Gara booted 14 points with a flawless kicking display to lead Munster's assault while Denis Leamy broke Wasps' resistance with a late try.
The holders would have progressed to the quarter-finals with a draw but ultimately could not even claim the losing bonus-point that guaranteed second place in Pool Five.
As it was, the defending champions finished third in Pool Five following Clermont's triumph over Llanelli and McGeechan conceded Munster were worthy winners.
"Simon's sin-binning was crucial but these are the things that you have to live with in big games," he said.
"We were on the receiving end of some tough calls and in a marginal game it's the little things like that become huge.
"Some of those decisions in the first half, had they gone for us, might have swung the pendulum in our way.
"We're disappointed. We said who missed out in this group would be unlucky because it was such a tough group.
"I think we played well throughout the group campaign but a couple of bonus points went begging.
"Clermont sending a second team to Munster was also quite instrumental in the outcome.
"We knew we'd have to get it 100 per cent right tonight to win but the penalty count went against us and Munster kept all the ball.
"Munster kept their noses in front at key times and it was always going to be difficult against them.
"I think we had the stronger pack so I'm not sure the wet conditions favoured Munster.
"On the night we can't complain about Munster winning."
Wasps captain Lawrence Dallaglio also questioned the decision to send Shaw to the sin-bin.
"Line-out and discipline was the key. We started well but I thought the turning point was Simon Shaw's sin-binning," said Dallaglio, who was also yellow-carded later in the game.
"I am not sure it was a sin-bin offence, a penalty yes, but in the context of the game, it helped them gain the momentum.
"Small decisions make a big difference but it is not sour grapes. Ultimately we were beaten by a side that played the conditions better than us."
Meanwhile, Munster boss Declan Kidney hailed his side who have reached the quarter-finals of the Heineken Cup for an unprecedented tenth successive year.
He said: "This is a special day. To beat a team of Wasps' calibre by this score was very impressive.
"It speaks volumes for all the players and the decision making out on pitch.
"We managed to scrape a point out of every game we played in the group stage and that was very important to qualification.
"I'm very proud of the boys. When it comes to matches like this we have to punch above our weight and that's what we do."
Kidney hailed O'Gara who also set up Leamy's try to cap a magnificent effort.
He said: "Ronan was absolutely magnificent. I can't speak highly enough of him. He's getting better and better."
But the victory was built on a titanic display from Munster and Ireland lock Donncha O'Callaghan who proved a thorn in the side of the visitors' line-out.
"Today was a cup final in itself and that was how we approached it," said O'Callaghan.
"We have huge respect for Wasps and we are thrilled to get out of the group.
"Every match was a dog-fight and it was brilliant to be a part of it. It was an immense effort.
"We would have settled for a quarter-final before the group began so not having a home tie doesn't bother us."