Fierce rivals New Zealand and South Africa go toe-to-toe in Auckland on Saturday in a crunch match that will be pivotal in deciding the outcome of this year's Rugby Championship.

Springbok captain Eben Etzebeth described the clash as "massive" and "the biggest challenge of the year" with plenty at stake for both teams.

Coaches Steve Hansen and Allister Coetzee may be midway through building squads and strategies for the 2019 World Cup, which may impact the quality of play, but it will not affect the onfield power and passion.

A victory to the All Blacks will put them in a commanding position at the head of the table with only two away games remaining, while the resurgent South Africans, with two home games left, need to win to keep their title hopes alive.

The Springboks, seeking their first southern hemisphere crown since 2009, had their unblemished start to the year ruined last week when a late penalty to Wallabies fly-half Bernard Foley saw them draw 23-23 with Australia.

The All Blacks also found themselves in trouble last week, trailing Argentina with 30 minutes to go, but while the Springboks faltered at the crunch, the New Zealanders produced their trade-mark late surge.

Although the final 39-15 scoreline looked convincing, there was enough looseness to give the Springboks a sense that they can take down their old foe.

The All Blacks "might have made one or two defensive errors" against Argentina, observed Coetzee, adding: "Small margins can be costly."

But Hansen was not fazed by the error count in the All Blacks high-risk approach

"It's not the finished product by any stretch of the imagination but it's well under control from a planning point of view," he said.

The return of Aaron Smith at scrum-half and centre Ryan Crotty, both rested against Argentina, should put New Zealand in a better position to cope with the expected Springboks rushed defence.

The speed of Smith's passing, and Crotty's instinctive reading of the game, are essential to the team's desire to play at pace which they will need to do with accuracy if they are to tire the big Springboks pack.

- 'Going to be physical' -

Hansen does not want the All Blacks to depart from their run-the-ball approach while South Africa have telegraphed that they are keen to provide the green-looking New Zealand back three with an aerial bombardment.

Fullback Damian McKenzie and wings Nehe Milner-Skudder and Rieko Ioane have only 20 Tests between them.

A pressure point for South Africa is to ensure they do not shut down early, as they did against Australia, with Coetzee saying they will need to go for "80-plus minutes" to win.

He knows the fitness of his forwards will be tested.

"We all know it's going to be physical. That's one thing the All Blacks know when they play South Africa and we also know. It's going to be very physical," he said.

In a late blow for the Springboks, scrum-half Ross Cronje was ruled out on Friday because of a stomach ailment and has been replaced by 45-Test veteran Francois Hougaard.

The last time the two teams met, in Durban last year, the All Blacks inflicted a record 57-15 defeat.

Teams (15-1)

New Zealand: Damian McKenzie; Nehe Milner-Skudder, Ryan Crotty, Sonny Bill Williams, Rieko Ioane; Beauden Barrett, Aaron Smith; Kieran Read (capt), Sam Cane, Liam Square; Sam Whitelock, Brodie Retallick; Nepo Laulala, Dane Coles, Kane Hames.

Replacements: Codie Taylor, Wyatt Crockett, Ofa Tu'ungafasi, Scott Barrett, Ardie Savea, TJ Perenara, Lima Sopoaga, Anton Lienert-Brown.

South Africa: Andries Coetzee; Raymond Rhule, Jesse Kriel, Jan Serfontein, Courtnall Skosan; Elton Jantjies, Francois Hougaard; Uzair Cassiem, Jean-Luc du Preez, Siya Kolisi; Franco Mostert, Eben Etzebeth (capt); Ruan Dreyer, Malcolm Marx, Tendai Mtawarira.

Replacements: Bongi Mbonambi, Steven Kitshoff, Trevor Nyakane, Lood de Jager, Pieter-Steph du Toit, Francois Hougaard, Handre Pollard, Damian de Allende.

Source: AFP