Graeme Smith and Hashim Amla wasted little time in guiding South Africa to the 101 runs needed to beat New Zealand, shortly before tea on the third day of the second Test at Seddon Park in Hamilton on Saturday.
Skipper Smith was unbeaten on 55 and Amla on 46 as the visitors wrapped up a nine-wicket victory that gives them a 1-0 lead in the three-match series.
Alviro Petersen was the only wicket to fall when he nicked a Doug Bracewell delivery to wicketkeeper Kruger van Wyk for one before Amla and Smith combined for a rapid 98-run partnership in 82 minutes to take the visitors to 103 for one.
Vernon Philander had earlier wrapped up New Zealand's second innings shortly after lunch, with the hosts bowled out for 168, setting the visitors a modest victory target and plenty of time to reach it.
Both batsmen failed to score after the break with Williamson knicking a catch to Mark Boucher off Philander, while Bracewell was bowled by an inswinger from Morne Morkel after the tall South African had set him up with a succession of deliveries that moved away.
Mark Gillespie (14), with two fours and a six, and Brent Arnel (eight not out) provided some lusty blows but the innings was ended when man of the match Philander bowled Chris Martin for a duck to give him figures of 6-44.
He also took 4-70 in the first innings to earn him a 10-wicket match haul for the second time in his six-Test career.
New Zealand, who had resumed on Saturday on 65-4, had lost two wickets before lunch when Daniel Vettori (21) was caught by Boucher after a gem of a bouncer from Jacques Kallis and Kruger van Wyk was bowled by Philander for 20.
The visitors had established a handy first innings lead courtesy AB de Villiers' top score of 83 and the tail producing 165 runs after Gillespie had taken career best figures of 5-59.
Scorecard
New Zealand (1st innings): 185
South Africa (1st innings): 253
New Zealand (2nd innings): (overnight 65-4)
R. Nicol b Philander 1
M. Guptill c Amla b Steyn 1
B. McCullum lbw b Philander 5
R. Taylor lbw b Steyn 17
K. Williamson c Boucher b Philander 77
D. Vettori c Boucher b Kallis 21
K. van Wyk b Philander 20
D. Bracewell b Morkel 0
M. Gillespie c Boucher b Philander 14
B. Arnel not out 8
C. Martin b Philander 0
Extras: (lb-4) 4
Total: (all out, 67.5 overs) 168
Fall of wickets: 1-1, 2-7, 3-7, 4-64, 5-99, 6-141, 7-142, 8-142, 9-160.
Bowling: Steyn 16-5-31-2; Philander 15.5-3-44-6; Morkel 13-5-26-1; Tahir 17-2-52-0; Kallis 6-3-11-1.
South Africa (2nd innings):
G. Smith not out 55
A. Petersen c van Wyk b Bracewell 1
H. Amla not out 46
Extras: (nb-1) 1
Total: (for one wicket, 19.5 overs) 103
Fall of wickets: 1-5
Bowling: Martin 3-1-18-0; Bracewell 5-0-14-1; Vettori 2-0-2-0; Gillespie 4-0-24-0 (nb-1); Arnel 3-0-18-0; Williamson 2-0-23-0; Nicol 0.5-0-4-0.
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