So, even borne along on a tide of emotion, the Springboks could be excused a certain apprehension. Most people imagined New Zealand rugby was becalmed but this was a misapprehension based on what happened last year, more Test defeats than victories, and was just as Mains had planned all along.
"We were pretty pleased to be underrated because it let us go about our business without too many people taking too much notice of us," he said.
For all the scepticism he has experienced in New Zealand during his occasionally troubled tenure as coach, Mains needs only point to his team's accomplishments here to be fully vindicated. He was once described by an Australian journalist as "the man with the Mona Lisa smile" and he is now having the last laugh.
"Right from the beginning, when I started in 1992, we planned a four- year strategy in which our first decision was what sort of rugby New Zealand would have to play to be successful at the 1995 World Cup," he said. "We looked back on our '87 and '91 campaigns, decided what we wanted and then realised we couldn't play it that way for four years because everyone would know what we were going to do and would counter us.
"So we decided to try out a few different tactics and game-plans along the way but if you look back to our Scotland Test in 1993 [won 51-15] and last Sunday's semi-final against England you will see some similarities. There were games when we tried things out and then didn't try them again so that people wouldn't twig.
"We didn't intend to lose any Test but winning a particular Test was not the ultimate goal and we weren't prepared to show our hand. We didn't finally refine our style until quite recently because if the players had known specifically what they were going to do six months ago it would have been old hat by now."
This turns on its head the rugby theory about the best long-term planning being the short-term expedient of winning the next match.
Mains, 49, an Otago full-back who won four caps in the Seventies, has been quite prepared for matches to be lost during the past three and a half years in the interests of perfecting both strategy and tactics and of assessing the widest range of candidates for his World Cup squad.
"There were hours and hours of going to games and studying video-tapes to see who had the skill-set we were looking for," Mains said. "Then it was a matter of making it work. I asked for four four-day training camps over our summer when we had to build team culture, the will to succeed, finishing it off with absolutely perfecting a few basic tactics and techniques that would allow this game-plan to work.
"We have to have quick ball and had to develop the technique of delivering that quick ball without it being spoiled by opposing players wanting to slow the game down. England posed a huge threat because Richards, Clarke and Rodber are the biggest loose-forward combination in world rugby and also have a reputation for shutting options down.
"We needed to make sure they couldn't do that. We knew if we could deal with the England back row there wouldn't be another back row who would make it any more difficult for us." And so it came to pass: the English trio's effectiveness was so sharply reduced that New Zealand rampaged through the first half and made the final with something to spare.
The stuff the All Blacks have been playing through the pool matches and the knock-out stage has been breathtaking to watch and breathless to defend against, a staggering combination of forward mobility and back-line dexterity which has discredited for ever notions of playing for position, percentage rugby and the need for gigantic forwards.
"We could have brought as big a forward pack as England's to this tournament," Mains said. "We have a few huge players, but they didn't fit into the type of game-plan we needed. We were influenced by the World Cup, changes in the laws, and the realisation that New Zealand doesn't have the biggest or strongest pack in world rugby any more as of right."
He makes it sound so simple, and the players have done so well for him in South Africa, that it is difficult at this distance to comprehend the pressure and criticism he has taken back home. Appointed after the unsuccessful 1991 World Cup, he withstood a challenge from John Hart, a former All Black and Auckland coach, at the end of 1992 and again six months ago, when the New Zealand Rugby Union council re-elected Mains by one vote.
This was scarcely an expression of confidence but Mains has carried on regardless of the council's equivocal support and the vast sums of money it has cost him to be constantly away from his building business near Dunedin in the South Island. "I have found it difficult and many times I've asked myself why I need all this.
"A lot of the public pressure in New Zealand was brought about by ignorance of what we were doing and by interest factions. Auckland are a law unto themselves. They were interested not in who was going to do the best job at the World Cup but in getting one of their own there. There are people prepared to undermine the All Blacks to get their way.
"It was good for the All Blacks to see me having to sustain that pressure. They saw that if I had to take it, then so did they and they came to my assistance at crucial times last year. It put the players and me on a level playing-field because they could see I had to go through the same rigours and pressure as they did."
This bonding has had a beneficial effect, as we have seen - and marvelled at - at this World Cup. Only last year John Kirwan, the once-illustrious wing, said Mains had "lost the plot", which may have had something to do with having been dropped, but no one would dare say anything like that after the rugby we have witnessed here over the past month.
Even the emergence of Glen Osborne, Jonah Lomu, Andrew Mehrtens and Josh Kronfeld is, it turns out, no accident. "We were quite prepared to experiment with players rather than just select a combination and say we want them to take us through to the World Cup," Mains said. "Obviously there was a core nucleus of players but in our final year of '94 during our National Championship we needed to find four players: full-back, wing, first five- eighth [outside-half] and open-side flanker."
Lo and behold, they were duly found, the frightening thing for the rest of us being that the aforementioned four are only at the beginning of their international careers. Imagine what they will be like by the next World Cup in 1999.
"A World Cup tournament is as good as two years' Test experience and the fact is that this team has not played together often enough to be at its absolute best," Mains said.
"It's like the All Black side who won the 1987 World Cup: they were at their best in '88. I would be very confident that, irrespective of what happens against South Africa, we are leaving behind the structure for another very, very strong era in New Zealand rugby." Help.Reuse content