If Ireland beat the All Blacks in their World Cup quarter-final in Tokyo tomorrow night it will be as much a triumph of their mental strength as their physical capabilities.
After more than 100 years of trying, the Irish have beaten the All Blacks twice in two years (in 2016 and 2018).
They will bring their own form of pressure with their famous defensive wall, but can they handle the mental pressure after losing their previous six World Cup quarter-finals? They were ranked No 1 in the world recently so if they can't progress at this tournament, when will they?
Richie McCaw, rarely out of the news back home despite not lacing up a pair of boots in four years, has been back in the headlines after he apparently provided the inspiration for the Australian Diamonds' netball win over the Silver Ferns because of his ability to handle the mental strain in the latter stages of the nerve-shredding 2011 World Cup final victory.
The lessons he learned following the 2007 World Cup failure at the quarter-final stage paved the way for the victory four years later and that of 2015. A large part of that was accepting pressure as a constant and embracing it as a challenge and opportunity to grow as a person and player.
Forensic psychologist and mental skills guru Ceri Evans also played a big part in teaching that.
Make no mistake, this is where all eight teams still in the World Cup want to be, but coach Steve Hansen was right when he said during the months preceding this tournament that the pressure is always on the All Blacks to deliver.
They're the defending champions, but it's just business as usual in terms of expectation. That's a little different for Ireland and the messages coming out of their camp this week reflect that.
"It's the biggest," Ireland first-five Johnny Sexton said. "In that regard, it's the most exciting. We said it after the Samoa [pool] game. We said no matter who we play, it'll be the biggest game of our lives.
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"You feel it when you wake up this morning and your mind goes straight to the game. Sleep will probably be a challenge this week."
Ireland prop Cian Healy, asked if this was the biggest match of his career, replied: "Definitely. It is a do-or-die game. We all understand that."
Another key advantage the All Blacks have is their leadership team of coach Hansen, skipper Kieran Read, plus others, which has been together for a long time. They know what it takes and they know what's coming over the 80 minutes at Tokyo Stadium.
In an interview with the Herald three years ago, Evans, the man who coached the All Blacks in the art of staying focused and flexible before the 2011 final against France, skills necessary for victory as history threatened to repeat itself, explained how unlocking the power of our minds was the key to attaining peak performance.
"The mind often limits us," Evans said, "and actually our body can do more, and that gets played out in different ways, even just in straight endurance. We think we've reached our threshold but the mind gives up first."
Asked about the All Blacks' mental performance in the 2011 final, Evans said: "The overriding sense of what they said of their experience at the time was that they were calm. They had debate. It wasn't all clear to them but they were able to discuss and debate and stay in the moment, make decisions, adapt to certain scenarios as they played out, and stay on task, rather than getting diverted by the situation ... From an external perspective it looked like they wobbled and had certain moments but they certainly didn't fold and, actually, they finished strongly."
Ireland might, too, but it will take an enormous and unprecedented effort.