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Leinster flanker Rhys Ruddock says that head coach Joe Schmidt’s “incredible impact” has made Ireland believe they can beat anyone in the world.
Ruddock will captain Ireland in Saturday’s Test with the United States, with Schmidt having made 14 changes from the team which beat New Zealand.
Schmidt, 53, will announce a decision on his long-term future next week.
“The impact he has on the group, and the belief over the long term, that has grown and grown,” said Ruddock.
“I think, from an outsider’s point of view, what you see, it’s pretty black and white. Joe’s impact, it’s there for everyone to see,” he added.
Schmidt has guided Ireland from eighth to second in the world rankings and overseen three Six Nations titles in five years, including a Grand Slam in 2018.
“It’s obvious he’s an incredible coach and he’s had an incredible impact on the environment as well in Leinster,” added Ruddock. “I was able to experience that first-hand and now with Ireland as well.
“We’re very lucky we’ve got him and the other coaches in the set-up doing such a great job.
“When I was younger I wasn’t always able to see quite what he was trying to teach, but as you progress you see those intricacies. His rugby knowledge is second-to-none.
“Up until now we’ve done well and done what we can, and the work done behind the scenes and producing big performances and results, that just feeds the belief all the time.
“But the most important thing now will be the next few months leading into the World Cup.
“We want to go into the World Cup in good form, but right now for the group is a big challenge this weekend.
“The Six Nations is further down the track, but that’s another incredible opportunity to test ourselves against some of the best teams in the world.
Ruddock’s status as captain of Ireland’s change XV underscores the impressive depth in Schmidt’s squad, especially in the back row.
The 28-year-old ranks among a number of Ireland’s extended squad already battling to prove their point for selection for next year’s World Cup party.
Peter O’Mahony, CJ Stander and Sean O’Brien are inked in as Ireland’s frontline back-row at present, with Josh Van Der Flier and Jordi Murphy pushing hard for places on the plane to Japan next autumn.
A strong showing from Ruddock this weekend could boost his own chances however, and he revealed his pride at being trusted by Schmidt to captain the side in Rory Best’s absence.
“Joe gave me the opportunity to captain Leinster when I was just 21, and he’s helped me grow as a leader from there.
“Being captain is a massive honour. Maybe it shows a little bit of respect from the players, that’s the main thing I would hope.
Asked if Saturday represents a World Cup trial for Ireland’s fringe players, Ruddock replied: “Not for us as a playing group. We live in such a bubble it really is week to week.
“All we’ve been thinking about is the USA and the threats they have.