Medium fast bowler Chris Martin grabbed three wickets in four balls after tea to seize the momentum for New Zealand as the hosts reduced South Africa to 191 for seven at the close of the opening day of the first Test in Dunedin on Wednesday.
Jacques Rudolph was 46 not out while Vernon Philander was on four at the close of the rain-effected day as New Zealand managed to wrest back the advantage after South Africa had returned from the tea break on a comfortable 86-1.
Martin, however, produced an inspired spell of bowling that began when Graeme Smith chased a wide delivery and was caught for 53 in the first over after tea, before Jacques Kallis was snared by Ross Taylor at first slip for a two-ball duck in his next over.
He then trapped AB de Villiers lbw off the next ball, though South Africa's limited overs captain reviewed the decision, which was upheld to leave the visitors struggling at 90-4.
"It took me a while to get going but there was a bit more intensity in the wicket, we got a little bit of nibble, got the ball to swing a little and put it in good areas," Martin said in a televised interview of his spell after tea.
Rudolph survived the hat-trick delivery then combined with Hashim Amla in rebuilding the innings with a 66-run partnership before Amla (62) was caught by Taylor after the ball deflected off Kruger van Wyk's gloves from the bowling of Daniel Vettori.
Mark Boucher was then run out for four after some smart work from Doug Bracewell at backward point before Dale Steyn was caught by Taylor after Martin Guptill had parried a simple catch to his captain, who bobbled the ball before grabbing it on the third attempt.
Alviro Petersen (11) was the only wicket to fall in the first session after rain delayed the start of play for nearly four hours, when he was trapped in front by left-arm seamer Trent Boult.
Petersen had initially been given not out by umpire Aleem Dar but Taylor used the decision review system to have it overturned.
"It was a good start but we need to get the wickets early tomorrow for it to show the good work we showed today," Taylor said. "But we're in a good position and so (I'm) semi-happy.
"We've got a big day tomorrow and hopefully we can make some early inroads and then make a good start with the bat."
Should South Africa sweep the three-match series 3-0, they will take over the world number one Test ranking from England.
South Africa (1st innings):
G. Smith c Nicol b Martin 53
A. Petersen lbw b Boult 11
H. Amla c Taylor b Vettori 62
J. Kallis c Taylor b Martin 0
AB de Villiers lbw b Martin 0
J. Rudolph not out 46
M. Boucher run out 4
D. Steyn c Taylor b Bracewell 9
V. Philander not out 4
Extras: (lb-1, nb-1) 2
Total: (for seven wickets, 59 overs) 191
Fall of wickets: 1-34, 2-86, 3-90, 4-90, 5-156, 6-161, 7-179
Still to bat: Morne Morkel, Imran Tahir.
Bowling: Martin 14-2-34-3; Southee 8-1-32-0; Boult 7-0-54-1; Bracewell 14-2-39-1 (nb-1); Vettori 15-4-31-1; Nicol 1-1-0-0.
New Zealand: Ross Taylor (captain), Martin Guptill, Rob Nicol, Brendon McCullum, Kane Williamson, Daniel Vettori, Kruger van Wyk, Doug Bracewell, Tim Southee, Trent Boult, Chris Martin.