Both were present at the Stade de France in Paris for the 13-8 win over defending world champions South Africa.
Ahead of play in the highly-anticipated Pool B clash, both were guests on ‘The Big Jim Show: LIVE’, Jim Hamilton’s RugbyPass TV programme.
McIlroy offered insight to Hamilton, a former Scotland rugby international, on Ireland’s development from past Rugby World Cup disappointments and his hopes for progress now beyond the quarter-finals.
“I think it’s a mental barrier more than a physical one and they have all the tools at their disposal, but the quarter-final of the World Cup has been their Achilles heel,” he said prior to the big game. “We all expect them to get there and this game (against South Africa) will be a big decider in how they get there.
“They had a tough time in Tokyo four years ago when they played New Zealand in that quarter, but they’ve come a long way since then and they’ve been able to overcome both France and New Zealand since then (in other tests).
"I think they’ve finally been able to get over that mental barrier, so I don’t think there’s anything standing in their way to do something they’ve never done before.”
McIlroy also singled out the support from Ireland fans across the sporting world.
“No matter where we play in the world, the support we get from the Irish fans, wherever it is, it’s incredible,” said McIlroy. “The fans travel to see their sports stars, and Paris is no different.
"But to actually be here and see the support that this team has, it’s amazing.
"Hopefully that support can carry them all the way in this tournament.”
“The last thing that’s happened in Ireland that would be as big as them winning a World Cup was this man (points to Lowry) winning the Open Championship in Portrush in 2019.
"If they get there, it’ll be a monumental achievement and they have to try to make the most of it.”
Lowry, who shares McIlroy’s love of rugby union, revealed a pre-tournament belief Ireland would finish as World Cup winners.
“Ireland are the best team in the world on paper and we all want them to win and go the whole way,” he said. “Tonight (the eventual win against South Africa) is a huge step towards that and I think this team has a chance to do something that will be remembered forever.
"Ireland might never have a chance like this again and I think this team has that chance.
“It’s very exciting for the country too...I was back there for a few days last week, but just being here today in France to see how many Irish people are here, like Rory says, we come out here in our numbers because we’re a great country to jump on a bandwagon (laughs).
"It’s going to be an amazing few weeks and hopefully it can be a successful one.”
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