Hashim Amla's unbeaten 106 guided South Africa to 325-4 at stumps on day one of the second test at St. George's Park on Friday after New Zealand made some early inroads only to wilt badly in the afternoon.
Amla moved South Africa back into a position of complete strength after Graeme Smith (54) and Jacques Kallis were dismissed in quick succession just after lunch and AB de Villiers failed to cash in on his half-century.
Amla had partnerships of 92 with Smith, 86 with De Villiers and 102 unbroken with Faf du Plessis (69 not out) to anchor South Africa, which won the first test by an innings and looked on course for another strong showing in the second.
Doug Bracewell led the bowlers with 2-70 but New Zealand has to win in Port Elizabeth to avoid a fourth series loss in five and was facing a large first-innings score by the South Africans after Amla continued his sparkling form from last year.
Amla was called into action after just 10 overs of the test when Alviro Petersen fell to a top edge to fine leg off Bracewell after a tricky opening spell from the New Zealand quicks. They made use of some early pace and bounce on the St. George's Park pitch in the first test here in six years.
But Amla, South Africa's outstanding batsman of 2012, wore them down and hit eight fours in his 19th test century and fifth in his last eight tests. That included his triple century in England and 196 in Australia in South Africa's back-to-back series wins on the road last year.
Amla was unbeaten alongside Du Plessis for the third significant stand he was involved in on the opening day, swinging it firmly in the home team's favor in the last session.
In the morning, Smith had to shake off a forceful blow on the helmet early on from Bracewell, but recovered after some brief treatment to push South Africa on after choosing to bat first. His stand with Amla put South Africa in initial control at 99-1 at lunch and then 121-1, but the Kiwis pulled it back early in the afternoon.
Smith gloved behind to wicketkeeper BJ Watling off left-arm seamer Neil Wagner. Kallis belted two successive pull shots to the boundary for his only scoring shots, then feathered an inside edge to Watling off Bracewell for 8 at 137-3, giving the Black Caps a chance of restricting South Africa.
Amla and De Villiers and then Amal and Du Plessis took it away from the tourists in the afternoon, though, as the momentum finally rested firmly with the South Africans. New Zealand managed just one more wicket - that of De Villiers - for almost the entire last two sessions.
De Villiers targeted offspinner Jeetan Patel in his 81-ball half-century, cracking the slow bowler through mid-wicket at least twice for boundaries. He passed 6,000 test runs but was too aggressive straight after registering his 31st test 50 and was caught on the edge of the in-field by Williamson off the persistent Patel.
Du Plessis kept Amla company for the final 29 overs as Amla moved serenely to three figures.
He had been dropped on 48 early in the afternoon as Kane Williamson put down a hard chance off a flashing cut shot at close backward point. Apart from that, Amla was typically composed and unruffled and reached 100 with another cut through backward point - this time a perfectly timed one.
The fast-growing Du Plessis went to a half-century with a powerful pull through mid-wicket as the Kiwis wilted in the late afternoon sun on the south coast.
Bracewell was brave for his two wickets, but attack leader Trent Boult was disappointing for his 0-74 and Wagner, who was brought in to beef up New Zealand's aggression with the ball, went for four runs an over in his 1-88. Patel finished the day with 1-60.