While the physical challenge of seven weeks of fierce competition at the Rugby World Cup sets it apart as the sport's ultimate test, it is mental strength that can prove the difference by the time of the final.
So says Dan Carter, the legendary former All Blacks fly-half, a three-time World Player of the Year, who experienced both triumph and despair in four World Cups.
But it is how Carter and the All Blacks engineered a mental transformation that explains their rise from serial chokers to record three-time winners, including back-to-back titles in 2011 and 2015.
Before that, however, they had to endure 24 years of anguish from their 1987 win on home soil until their second global title.
"The biggest learning for the All Blacks, especially from 2007 to 2011, was we put a lot of work into the mental side of our game," Carter says.
"It was becoming a bit of a joke about us being chokers and it being 24 years since the All Blacks had won a World Cup, and at every World Cup [after that] there was more and more pressure. Not only have you not won a World Cup for a long time, but all of a sudden not to win a World Cup in your home country is just something that isn't supposed to happen."
During Carter's first taste of World Cup rugby, in 2003, the All Blacks were beaten by tournament hosts Australia in the last four. But Carter was only a squad player then, and his anguish was nowhere near as profound as it was four years later.
The seismic shock of Cardiff in 2007, when France stunned the All Blacks 20-18 in a pulsating quarterfinal, still haunts Carter and his fellow countrymen.
Carter, who had to go off injured in that game, recalls: "We came unstuck in the quarterfinal of 2007 and we hadn't been put under that type of pressure before by the French team. We didn't have an answer and we didn't play well enough.
"The New Zealand Rugby Union, instead of changing coaches, they stuck with the same coaches [Sir Graham Henry and Steve Hansen] and everyone learnt lessons from that Rugby World Cup and, in a lot of things, we changed."
The appointment of a mental skills coach, Gilbert Enoka, was "hugely instrumental" in addressing the All Blacks' fragility under pressure, the 37-year-old says.
"We put tools in place to help us perform under pressure so if we did come under pressure in 2011, we were better prepared and were able to almost sort of walk towards that pressure rather than make it a weight on our shoulders."
As a result, when the heat was on in a nerve-shredding final against France in Auckland in 2011, the All Blacks' supreme self-belief helped them prevail 8-7. For Carter, however, this was a bittersweet victory as he was absent with a serious groin injury sustained in training ahead of the final pool game against Canada.
Carter's glorious career, in which he scored a record 1,598 Test points and which he is currently extending in Japan with Kobelco Steelers, is documented in the recently released biopic 'Dan Carter: The Perfect 10'.
His fairy tale finish in winning the 2015 World Cup in his 112th and final All Blacks appearance was perfect film fodder. But so was the suffering that came before it.
Persistent injuries, including his 2011 catastrophe, had led to crippling self-doubt and negativity assailing him, to the extent that he admits in his film that he felt "broken" and even cried uncontrollably in his hotel room at one stage.
"For me personally, a lot of the mental side is making sure that you're clear and focused in the heat of the situation," he explains. "I was over-thinking things, so I was often thinking about the result and becoming unfocused and forgetting about the process. I spent a lot of time with Gilbert just making sure that we brought things back to 'process, focus' and the result will take care of itself if you do that.
"[It helped] having someone there to talk to basically so you're not having to have those conversations in your own head [and can] express how you're feeling and sort of be vulnerable and just kind of open up."
A relaxed and rejuvenated Carter rolled back the years in the 2015 final with typical aplomb, scoring 19 points in a man-of-the-match display in the 34-17 rout of Australia.
While "relief" was the preponderant emotion in 2011, the All Blacks' Twickenham triumph brought them more "joy and satisfaction", Carter says.
"It was all about us leaving a legacy and doing something that no other international team had done before by winning back-to-back World Cups and being the first All Black team to win outside of New Zealand."
The landmark accomplishment owed much to the vast experience the team had at their disposal, Carter adds. Countries who have won the World Cup in the professional era post-1995 had an average of 50 caps per player in their starting XVs, with five and a half years' Test rugby experience behind each player. In 2015, Carter and captain Richie McCaw were among a clutch of multi-capped 30-somethings in the All Blacks ranks.
"We had some amazing experience in 2015 and there were [four] of us who were even there in 2007, so we had a bit of hurt and we knew what it took to lose a World Cup, which sounds a bit strange but you do get a lot of learnings from missing out," says Carter.
"I think that's why England will be strong [this year] because they have players that were involved in 2015 who will be hugely disappointed with their performance in not reaching the knockout stages."
What is Carter's blueprint for Rugby World Cup success, then?
"I think you need to separate Rugby World Cups from just normal Tests matches because they're completely different from anything you do and play at international level. You have to be better prepared because things are going to happen in that seven weeks that really challenge you.
"There are going to be injuries, there are going to be upsets and there's going to be a lot of drama just [from the] fact you're living together for two months, which is a new challenge and something you don't do in an international window.
"As soon as you get into that mindset of: 'Okay, this is going to be different', then you prepare for those challenges that you're going to face."
Carter believes the All Blacks, who beat South Africa 23-13 in their Pool B opener, are well primed to secure a historic 'three-peat' in Japan, despite not being rated as highly as the stellar teams he played for.
"The All Blacks love creating history and doing what no other teams have done before. If this team can go and do a three-peat, that's setting the bar even higher for the future.
"They've got the talent to go all the way. They've got a strong management group led by Steve Hansen, who'll be coaching at his fifth World Cup. That experience is huge.
"They play a good, exciting style of rugby. They haven't gelled 100 per cent yet this season but as you saw in the pool stages of the last World Cup, we just kind of got better and better as the competition goes on.
"I'm sure we'll see that from the All Blacks throughout the tournament."
Carter believes that England, who have won their opening two games of the tournament, will serve as the champions' greatest challengers.
"England are moving in the right direction as well and have had some great performances, created some depth in their squad and are playing some good rugby.
"I could name four or five other [challengers]. You look at the results over the last 12 months and all teams are beating each other and you can't say it will just be one of two teams that will win this World Cup.
"I think it'll be the closest we've seen in a long time and that's exactly what you want as a spectator and as a fan."