Ireland were correctly pinged at scrum time against New Zealand on Saturday, according to former South African prop BJ Botha.
Andy Farrell's men became the latest Irish team to fail to get past the quarter-finals of a World Cup as they came up just short against the All Blacks in an absorbing encounter at the Stade de France.
The post mortem has pointed to scrum issues that Ireland suffered, as they conceded three penalties at crucial moments in the game.
For Botha, who was in the South African squad for their World Cup victory in 2007, the calls were fair.
"I've looked at them and I do believe they were," he said on the RTÉ Rugby Podcast.
"[Andrew] Porter for me is an unbelievable player but if you look at the weakest part of his game it would be scrummaging. He's shown that.
"I've looked at the games and he was quite lucky against South Africa. [Ben] O'Keeffe went after him after the first scrum and said that you need to lift your elbow up. It was a clear penalty.
"Set piece is paramount in these cup games. When that cycle turns at scrum time, it is first and foremost set by that first scrum; it sets the tone and we build momentum through it.
"When doubt seeps in you get into a sort of survival mode. Even at that pro level you're thinking harder about the next scrum, decisions going against you and how do I correct this.
"It definitely overflows into other parts of your game. You're trying to change something, which you shouldn't do - you trust the process.
"Momentum is big from a mental perspective and it can affect other set pieces, such as the lineout.
"New Zealand came and they knew they could take them on there. When you create this momentum it's difficult for the ref to change that around.
"It takes a real proper ref to make a big decision. [Wayne] Barnes is one of the better ones on the scrum side and he made some good decisions."
Listen to the RTÉ Rugby podcast on Apple Podcasts, Spotify or wherever you get your podcasts.
Watch Argentina v New Zealand in the Rugby World Cup semi-finals on Friday from 7.35pm on RTÉ2 and RTÉ Player, follow a live blog on RTE.ie/Sport or the RTÉ News app
