New Zealand captain Kieran Read said Saturday's highly anticipated clash with South Africa is one of the biggest matches of his career as the All Blacks launch their bid for a record third consecutive world crown.
The Pool B match-up at Yokohama features two of the most successful sides in rugby history, and two of the sport's greatest rivals, in a tournament where no team has lost a pool match and gone on to lift the trophy.
The pre-match exchanges focused on whether referees do or do not have a bias towards the All Blacks, but the match reality centres on the the rapid improvement of the Springboks since they were caned 57-0 by New Zealand two years ago.
Rassie Erasmus came in as coach and instigated an approach that hinges on kicking for territory and then regaining the ball through forward power.
It has resulted in a margin of no more than two points in the next four matches against the reigning world champions, setting up what could be a classic at the 70,000-capacity International Yokohama Stadium.
The All Blacks, meanwhile, have tweaked their roster but remain comfortable with an emphasis on striking out wide, and the contrast in styles may well see the outcome decided by one error from either side.
"South Africa in our opening game of the tournament is going to be one of the bigger games you play over your career," said Read, the 122-Test veteran who featured in both the 2011 and 2015 World Cup finals.
The All Blacks-Springboks final dress rehearsal before Japan ended in a 16-16 stalemate in Wellington two months ago.
It was a result that delighted Erasmus who has stuck with the same line-up apart from the return of a fit-again Siya Kolisi, and reaffirmed his game plan.
The aerial assault led by halves Faf de Klerk and Handre Pollard is perfect for Japanese conditions where humidity and possible wet weather will make the ball slippery.
It lays the groundwork for the heavyweight 'Bok forwards battle for turnover ball and for the backs to attack when they sense the All Blacks' defensive patterns are in disarray.
"Kicking is going to play a big part but somehow you have to score points. You can't just get by on penalties and drop goals," Erasmus said.
The All Blacks have reacted by dropping prop centurion Owen Franks and relegating Ben Smith to the bench, while Rieko Ioane, once a first-choice wing, cannot even make the matchday 23.
Instead, coach Steve Hansen has gone for the youthful exuberance of wings George Bridge and Sevu Reece, while devising a twin playmaker role for Beauden Barrett at fullback with Richie Mo'unga wearing 10.
They are all capable under the high ball as well as being noted counter-attackers, with Bridge and Reece the try-scoring weapons for the Super Rugby champion Canterbury Crusaders, while Barrett is a two-time world player of the year.
Nepo Laulala comes into the front row in a rethink about the requirement for props, with the All Blacks favouring mobility over muscle in an attempt to tire the heavyweight South African pack.
Read says there is "nothing special" about the rapid revival of the Springboks over the past two years.
"They do it well which is being physical, kicking well... and using their strength which is their maul.\
"We know what's coming our way and we're in a good place to put a plan out that we think is going to match it."