The Proteas had come out to bat after tea just long enough for Elgar to register his first Test century — having been on 91 at the interval — and they used the remaining 24 overs in the day to dispatch the New Zealand top order and leave them nowhere near the 326 needed to avoid the follow-on.

Martin Guptill was the first to go for just one run, edging behind off Dale Steyn to be caught by Alviro Petersen, and two overs later Kane Williamson followed for four, also nicking into the slips to give Steyn a second victim. Dean Brownlie scratched out 10 runs but was thoroughly undone by a superb delivery from Rory Kleinveldt which struck the glove before carrying to AB de Villiers.

Review wasted
And Kleinveldt soon had another victim with Daniel Flynn wasting a review when trapped plumb lbw without having registered. Opener Brendon McCullum had stuck around through the chaos to score a watchful 13 off 61 balls, but he was the next to go, undone by the spin of Robin Peterson to be caught behind by Jacques Kallis.

Colin Munro followed for a golden duck moments later, caught by Elgar at short leg, and Doug Bracewell barely avoided edging the hat-trick ball behind with New Zealand reeling. BJ Watling reached the close unbeaten on 15 — the highest score in the New Zealand side — while Bracewell was on three.
Earlier, it was the Du Plessis and Elgar show as the pair put South Africa in complete control.

Amla had been the star yesterday, but he added only four to his overnight 106 before edging a Trent Boult delivery behind down the offside, clearing the way for today’s stars to shine. Du Plessis, who resumed on 69, scrapped his way to 99 at lunch on a slow morning, affected by wet conditions after a delayed start.

But if he found his lunch tough to stomach he did not show it as he reached his second Test century by smashing a Jeetan Patel delivery out of the ground. He had yesterday brought up his 50, and South Africa’s 300, with the only other maximum of his innings.

Elgar, meanwhile, quickly reached his first Test half century, looking far better than the player who began his Test career with a pair against Australia and a nervous 21 in the first match of this series. Together they tried to pick up the pace and Du Plessis bashed his way to 137 before falling, mistiming a shot to give McCullum an easy catch in the covers off Colin Munro.

Source of angst
Du Plessis’ progress had been a particular source of angst for New Zealand, who missed the chance to remove him on 42 yesterday when replays showed he gloved a delivery to Watling only for the Black Caps to decide against referring the decision.u00a0Peterson scored only eight in a brief cameo before also falling to Munro, caught at mid-wicket by Patel, but Elgar continued to make strong progress and reached tea on 91.