"The physical challenge will be huge, as it always is, and the team that executes their game with the greatest effectiveness, clarity and intensity will be the one that comes out on top.
Coles' selection is a play-or-perish approach, a chance to get a serious gauge on his progression as the All Blacks look long-term towards the next World Cup.
Age is posing a question about Mealamu's quest to last a further 2 years at the top while Hore is understood to be leaving the international game later this year.
Whatever the outcome for the two senior hookers, more have to be introduced to the All Black sanctum.
Coles made that jump on last year's tour to Europe after previous choices Hika Elliot and Corey Flynn were overlooked. They are still in the outside lanes, with Liam Coltman, Rhys Marshall and Nathan Harris linking up at team training sessions this season.
Meanwhile, Coles will get a Springbok welcome from Bismarck du Plessis, who is returning to test rugby after a year out with a knee injury.
It will be a great measure for Coles because Du Plessis is as rugged as any hooker on the world circuit and, like Hore, is a remarkably consistent menace in mauls.
A month ago there was a surprise when Coles was released to ITM Cup work, rather than the Bledisloe Cup bench in Sydney. The selectors explained they wanted to give him more match play and he was on the test bench for the last two internationals.
His sudden promotion against the Springboks will provoke even greater astonishment.
However, it is in line with other choices the All Black selectors made, like the promotions of Aaron Smith, Julian Savea, Beauden Barrett, Sam Cane and Luke Romano last year.
They continued that work with Charles Piutau, Francis Saili, Matt Todd, Steven Luatua and Jeremy Thrush in this campaign.
Blindside flanker Liam Messam is reinstalled for Eden Park after his hamstring strain and takes over from impressive newcomer Luatua, who will also cover lock from the bench.
"In selecting the team, there were some tough decisions to be made, none more so than between Liam and Steven," said Hansen. "In the end we have gone for Liam's extra experience and physicality, but we also know that Steven will enter the contest at some stage."
Cane will play his 10th test as a replacement for injured captain Richie McCaw and in midfield, Ma'a Nonu rejoins the backline after a week's rest for his ankle problem.
All Blacks v Springboks
Eden Park, Saturday, 7.35pm
All Blacks: Israel Dagg, Ben Smith, Conrad Smith, Ma'a Nonu, Julian Savea, Daniel Carter, Aaron Smith, Kieran Read (c), Sam Cane, Liam Messam, Sam Whitelock, Brodie Retallick, Owen Franks, Dane Coles, Tony Woodcock
Reserves: Keven Mealamu, Wyatt Crockett, Charlie Faumuina, Steven Luatua, Matt Todd, Tawera Kerr-Barlow, Beauden Barrett, Charles Piutau.
Springboks: Zane Kirchner, Willie le Roux, JJ Engelbrecht, Jean de Villiers (c), Bryan Habana, Morne Steyn, Ruan Pienaar, Duane Vermeulen, Willem Alberts, Francois Louw, Flip van der Merwe, Eben Etzebeth, Jannie du Plessis, Bismarck du Plessis, Tendai Mtawarira
Reserves: Adriaan Strauss, Gurthro Steenkamp, Coenie Oosthuizen, Juandre Kruger, Siya Kolisi, Jano Vermaak, Pat Lambie, Jan Serfontein.
