And this is where they might already have an edge on the Boks. In previous World Cups, the knockout stages have ushered in a defence-first, conservative game plan, but the All Blacks - and, incidentally, Argentina in their 43-20 win over Ireland - showed that an ambitious, attacking game plan can also pay big dividends.
It's doubtful whether the South Africans have that trust in their game or the players to implement it. After losing to Japan they have reverted to type and, without expressly saying it today, the All Blacks are expecting a game plan from their opponents based around big runners coming straight at them.
"They've probably tweaked a number of things since the Rugby Championship," Foster said. "I don't want to say too much about that but they've obviously adopted a style which is a style they think they need to win the World Cup. We're working hard to get our style right to get to the same objective.
"We take our best guess at how we think they're going to play us. For the last two or three games they've played a game which generally suits them historically and they've done it very, very well."
All Blacks loose forward Jerome Kaino, back to his muscular best against the French, said: "Their forward pack is a huge part of their game and it's what gets them going. I think we'll see much of the same but for them to intensify and lift their skill level."
Foster, who said wing Nehe Milner-Skudder was progressing well from a shoulder knock at the Millennium Stadium, didn't wear the same positive expression when referring to prop Wyatt Crockett's groin injury. "Wyatt, we're not really sure about.
"It's a possibility [that he will be ruled out], but there has been some progress and let's see what happens in the next 24 hours."
Every All Black will be put through an extreme physical examination by the Boks at Twickenham on Sunday morning, but another thing in their favour is their fitness - which allows them to retain their skill levels deep into matches.
That ability to play for harder and longer than their opponents has been something they have worked hard at during their time in the United Kingdom.
"We want guys to play for 80 minutes fast, aggressive rugby and we've worked hard on that. It's not just the fitness, it's also the squad - the ability to bring guys off the bench to really add value. We've certainly seen the benefits of that recently," said Foster, who added that part of allowing his players to express themselves was to know when to take the hands off the reins.
"We like to let our guys make decisions, we believe it suits our athletes ... it involves letting go a little bit as a coach and making sure you give space for them to make decisions and being aware they're not always going to be right but that's the way that they can express themselves."
- By Patrick McKendry in London
