Beauden Barrett will start at full-back as New Zealand begin their attempt to win a third straight World Cup against South Africa on Saturday.

Coach Steven Hansen has opted for Crusaders' Richie Mo'unga at fly-half, with inexperienced wings George Bridge and Sevu Reece also in the XV.

Only five of Barrett's previous 48 All Black starts have come at 15.

Siya Kolisi leads a South Africa team with a back three of Cheslin Kolbe, Makazole Mapimpi and Willie le Roux.

Gloucester's Franco Mostert forms the second row with Eben Etzebeth.

Coach Rassie Erasmus said the line-up, which beat Japan 41-7 in their final warm-up, was his "best side".

New Zealand and South Africa, favourites and second-favourites to win the tournament respectively, have met three times over the past 12 months, each securing narrow victories before July's 16-16 draw in Wellington.

Both teams have been preparing for wet and humid conditions in Yokohama, with rain forecast just before kick-off and temperatures expected to be over 20C.

"It's going to be a massive challenge with the rain they're predicting. Everyone's talking about the slippery ball and the wetness. Kicking is going to play a big part," said Erasmus.

The South Africa coach had suggested earlier in the week that New Zealand's recent dominance of the international game meant referees gave them preferential treatment.

However, All Black counterpart Steve Hansen said his comments were a transparent attempt to sway French official Jerome Garces, who has sent off Scott Barrett and Sonny Bill Williams while in All Black action over the past couple of years.

"Whilst I have a lot of respect for South Africa and Rassie, I don't agree with what he's doing," said Hansen.

"He's trying to put pressure on the referees externally, and they are under enough pressure already. They don't need coaches to be doing what he's doing."

Teams

New Zealand: B Barrett; Reece, Lienert-Brown, Crotty, Bridge; Mo'unga, Smith; Moody, Coles, Laulala, Whitelock, S Barrett, Savea, Cane, Read (c).

Replacements: Taylor, Tu'ungafasi, Ta'avao, Tuipulotu, Frizell, Perenara, Williams, Smith.

South Africa: Le Roux; Kolbe, Am, De Allende, Mapimpi; Pollard, De Klerk; Kitshoff, Marx, Malherbe, Etzebeth, Mostert, Kolisi (c), Du Toit, Vermeulen.

Replacements: Mbonambi, Mtawarira, Nyakane, Snyman, Louw, H Jantjies, Steyn, Kriel.

What they said

New Zealand coach Steve Hansen: "Any combination of players in our squad could have justified their selection. But in the end we believe the 23 we have selected is the right group for this opposition.

"To perform at our very best, we'll have to play with real clarity, intent, energy and clear heads. Both teams will have their moments and it'll be our job to ensure we limit theirs and take full opportunity of ours."

South Africa coach Rassie Erasmus: "You couldn't say there is a favourite. I think we have a healthy respect for each other's capabilities but it will come down to a small moment to decide a big game in the end," the coach said.

"Our job is to focus on executing our plan and our skills to the best of our ability and hope that that is enough to overcome a New Zealand team that will be doing exactly the same."

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