South Africa have named an unchanged side for their mouthwatering Rugby World Cup opener against New Zealand in Yokohama on Saturday.

Coach Rassie Erasmus will stick with the same XV and eight replacements that saw off hosts Japan 41-7 in a warm-up game two weeks ago.

It represents the first time the Springboks have stuck with the same side since the 2015 World Cup semi-final, which New Zealand edged 20-18 at Twickenham, while number eight Duane Vermeulen will win his 50th Test cap.

The only alteration from the team that played out a 16-16 Rugby Championship draw against the All Blacks in Wellington in July is fit-again captain Siya Kolisi starting at openside flanker in place of Kwagga Smith.

"We have 31 players in the squad, any of whom I would be happy to select, but this is a line-up that has worked well as a starting combination with real momentum to come from the bench," Erasmus told a news conference.

"They have emerged together over the past 18 months as our game has developed and matured. We've prepared well and we're looking forward to what will be another extremely close match.

"I think the thing that makes it special, if you ask anybody right now who is going to win this Test match, you know, I don't think anybody can bet on any of the two teams.

"I guess if you ask our boys we think we've got a really good chance, I think if you ask Steve [Hansen, New Zealand coach] and their team, they'll think they think they have a really good chance. Hopefully the referee is not too sure."

Indeed, referee Jerome Garces found himself to be the focus of what appeared to be some pre-match mind games on Erasmus' part.

"Even referees buy into that respect [for the All Blacks]," he said. "And because you are playing so well, referees almost find it tough to penalise you in 50-50 decisions."

"I think it was a well-known fact that it was really tough at times when teams were under the pump, some of the 50-50 decisions went their way because they deserved that, being number one for so long."

After taking on the world champions, South Africa will also face Italy, Namibia and Canada in Pool B.

South Africa team to play New Zealand: Willie le Roux, Cheslin Kolbe, Lukhanyo Am, Damian de Allende, Makazole Mapimpi, Handre Pollard, Faf de Klerk; Steven Kitshoff, Malcolm Marx, Frans Malherbe, Eben Etzebeth, Franco Mostert, Siya Kolisi, Pieter-Steph du Toit, Duane Vermeulen

Replacements: Bongi Mbonambi, Tendai Mtawarira, Trevor Nyakane, RG Snyman, Francois Louw, Herschel Jantjies, Frans Steyn, Jesse Kriel