Ntini and Steyn fire before rain
When Ntini and Steyn tore through the top order, leaving New Zealand reeling at 28 for 6, the match was hurtling towards a conclusion before lunch. However, as throughout the Test, when the ball gets softer the venomous qualities of the pitch do start to reduce. That does not mean that batting was ever comfortable, though, and Marshall will be wearing the marks of his resistance well into the next match as he was left battered, bruised and patched up. He took a crunching blow to his ribs, which left him writhing around, but although he was down, he wasn't out. The same could not be said of the rest of New Zealand's top order.
The signs from the start of this Test were that a fourth-innings chase would be a tough prospect and quite how tough became clear as Ntini and Steyn charged in with the new ball. Ntini began the demolition duties, as he has so often this season, with a double strike in his second over.
Peter Fulton could do very little with the delivery he received as it rose past his chest and flicked the bat. To their credit, however, New Zealand tried something different by sending Kyle Mills in at No. 3 - almost as a new-ball watchman - to try and negotiate the toughest period of the innings. But the conditions would have tested the highest class of batsmen, so a player more used to No. 10 was always up against it. He managed to survive just one ball before edging to Boeta Dippenaar who dove forward at first to cling onto an impressive catch.
Stephen Fleming, on a pair in his 100th Test, managed to register his first runs of the match but never suggested permanency in the middle and an airy drive handed Steyn his first scalp of the innings and a second wasn't far away as Scott Styris joined the procession. Meanwhile, there was no stopping Ntini. He continued the slide by sending Nathan Astle packing and cleaned up Oram with a shooter. Astle's slash to third slip would often, with his team in the mire at 23 for 4, be called irresponsible, but there was little point in pushing and poking. It was only a matter of time before a delivery came down with the batsman's name on it.
Ntini is enjoying a memorable match and even contributed a useful 16 as South Africa's last pair hung around for a frustrating half hour at the start of the day. But if New Zealand had taken Ntini's frolics as a sign that batting was possible, they were soon given a harsh reminder of reality.
Some of the sting had gone from the South African attack - and the pitch - after lunch as Brendon McCullum chanced his arm in a typically pugnacious counterattack. He targeted Steyn, in a similar manner to the first innings, but this time South Africa's latest new-ball recruit maintained his composure. Steyn was rewarded for perseverance when McCullum's attacking instincts brought his downfall. But it was really the best way to go with deliveries flying past throats and others shooting past ankles.
The poor light that cut into the start of the afternoon returned to bring an early tea and soon swallowed the final session allowing New Zealand to nurse their bruises in the dressing room. However, the morning session demise was so dramatic that it will take a long, dark day tomorrow, or one of Centurion's famous downpours, to allow them an escape route.
How they were out
Makhaya Ntini lbw b Vettori 16 (299 all out)
Played back, beaten by a quicker one
Peter Fulton c Boucher b Ntini 4 (5 for 1)
Lifter took shoulder of the bat
Kyle Mills c Dippenaar b Ntini 0 (5 for 2)
First slip diving forward and right to hold low edge
Stephen Fleming c Kallis b Steyn 6 (17 for 3)
Loose shot to outswinger
Scott Styris c Boucher b Steyn (23 for 4)
Regulation outside edge
Nathan Astle c de Villiers b Ntini 2 (26 for 5) Back-foot slash to third slip
Jacob Oram b Ntini 2 (28 for 6)
Ball scooted through, took off stump
Brendon McCullum c Dippenaar b Steyn 33 (73 for 7)
Forcing edge to first slip
Andrew McGlashan is editorial assistant of Cricinfo