Centuries from Kane Williamson and Rachin Ravindra at entirely different stages of their careers – and both of varying styles – made South Africa pay for the lack of experience and pace, and the chances they put down of both batters. The duo had put on 219 runs for the unbroken third wicket by the end of the first day to deflate a spirited South Africa line-up that had reduced the hosts to a tricky 39 for 2 in the first session.

Williamson was the more patient and circumspect of the two as he put a scratchy start behind him, whereas Ravindra smoked a six on his 11th ball to get going for his best Test score as both batters picked up pace in the last session to just about touch the run rate of three an over.

Ravindra and Williamson had to steer New Zealand out of troubled waters after debutant Tshepo Moreki started his Test career with a first-ball wicket by trapping Devon Conway lbw for 1 in the second over of the game. In his accurate first spell of 5-1-10-1, Moreki beat Williamson three times in 15 balls for just five runs.

Dane Paterson also tested the batters with his seam movement with wobble seam, and he soon drew Tom Latham’s outside edge for 20. The jitters continued as Williamson was nearly run-out when Ravindra tapped his fifth ball towards cover point for a quick single, only for the throw to be wayward. Had Williamson been dismissed, the hosts would have been 44 for 3 then.

Ravindra’s start was much more confident, as he welcomed Moreki back for a second spell with a six over the long-leg boundary. Moreki continued to impress nonetheless, and even drew Ravindra’s edge three balls later, but it fell well short of second slip. Ravindra enjoyed some more luck off Moreki on 23 when his inside edge just missed the stumps which made him a bit more watchful.

The duo batted patiently through a wicketless second session of 27 overs for just 60 runs, with plenty of leaves and blocks because of the tight bowling from the four South Africa quicks. South Africa were fielding an all-pace bowling attack and six debutants in Mount Maunganui, including their captain Neil Brand. It was the first instance by a Test nation apart from Ireland and Afghanistan who had their captain on debut when the side wasn’t playing its first Test.

But the conditions started to get better for batting after the initial swing subsided and once the ball got older. Williamson opened up with imperious boundaries off Moreki in consecutive overs, and Ravindra soon caught up when he broke the shackles against Paterson with a cover drive and a mighty pull for a one-bounce four.

While Williamson played the ball very late and used soft hands to ensure his edges weren’t carrying, Ravindra drove, scythed and pulled the loose deliveries with hard hands and a lot more punch. Williamson got a life on 45 just minutes before tea when he uncharacteristically slogged against Ruan de Swardt’s medium pace, but the leading edge was shelled by Edward Moore while running back from extra cover.

And Williamson reached his fifty in the next over with a boundary, while Ravindra reached his own in the over after the break. Both scored a lot more freely with boundaries to tick at above four runs an over in the half hour after the tea break as Ravindra closed in on his partner. By then, Duanne Oliver’s pace had started to drop below 125kph, and South Africa’s captain Neil Brand came on to bowl left-arm spin but for no success.

Soon after, Ravindra got a life on 80 when his top edge flew to deep backward square leg where Olivier ran in and dived forward, and got both hands to the ball, but couldn’t hold on. As South Africa started bowling shorter consistently before the second new ball was taken, Williamson pulled to reach his 30th Test century – off 241 balls – while Ravindra’s landmark moment came in the next over, off 189 deliveries.

South Africa’s fortunes didn’t change even after the second new ball, which was slapped straightaway for a four by both batters. Ravindra continued to collect boundaries off Moreki, whether he pitched it full or short, to overtake Williamson and finish the day unbeaten on 118, ten ahead of the former captain.