South Africa 152 for 4 (Amla 48, Rossouw 38) beat New Zealand 151 for 8 (Williamson 42, Guptill 42, Wiese 2-24) by six wickets
Scorecard and ball-by-ball details
AB de Villiers did not do what he was supposed to - keep wicket and open the batting - because Faf du Plessis' knee injury meant he had to captain instead. In that role, he did exactly what he was supposed to when he put New Zealand in to bat, managed his bowlers well to haul them in and then set up a successful chase.
South Africa slowed New Zealand's speedy start, which saw them race to 63 without loss after seven overs, to ensure they only added another 88 runs in the remaining 13 overs. Even on an early season surface that did not seem to have the same pace, bounce and carry as a South African strip normally does, that was not enough. South Africa were barely troubled as de Villiers shared a second-wicket stand of 50 with Hashim Amla, who top-scored with 48 as South Africa claimed a comfortable win.
The home side seized the advantage thanks to Aaron Phangiso, who started the squeeze with an opening over that included the wicket of Kane Williamson. New Zealand threatened to make it a one-man show before he was beaten by flight and stumped for a 21-ball 42.
Phangiso's breakthrough came after South Africa's seamers were off to a wayward start and allowed Martin Guptill and Williamson to settle. Kyle Abbott hoped to make use of early season conditions with the short ball but offered too much width, Kagiso Rabada veered down the leg side too often and Morne Morkel went too full. Williamson's driving and flicking was authoritative and New Zealand's foundation was laid.
But Phangiso rocked it when, after fluffing the opportunity to run out Williamson when Guptill sent him back earlier in the over, he drew the New Zealand captain forward and found him short of his ground.
Guptill had been accumulating steadily while Williamson attacked and tried to continue the aggressive approach with George Worker. David Wiese assisted by providing more room for Guptill and Worker struck the first six - in the 10th over - when he sent Phangiso over square leg and into the stands. With Morkel still struggling for rhythm, New Zealand could rebuild but then Guptill got a little too casual.
He was late in sliding his bat in at the striker's end after attempting a single off Wiese and Morne van Wyk reacted quickly to get the bails off. Colin Munro was caught by a diving AB de Villiers at mid-on off the next ball and South Africa had successfully clawed their way back. They could have seized the advantage when Worker pulled Phangiso to long leg in the next over but the ball went through Morkel's hands.
Phangiso only had to wait another over to have the last laugh. He trapped Worker lbw with a flat ball darted in on middle that struck the back pad as the batsman missed the slog sweep. By then New Zealand were well into their collapse after Grant Elliott had holed out the over before.
South Africa's see-saw evening in the field continued when Wiese dropped Tom Latham and then ran-out Luke Ronchi with a direct hit. New Zealand lost seven for 40 which included two wickets for Rabada in the final over to set South Africa a target they were happy to chase.
Van Wyk, making his comeback after being left out of the Bangladesh series, gave himself time to settle in before announcing himself off Mitchell McClenaghan. Van Wyk lofted the left-handed bowler over the covers, behind square and then into the off-side stands to start South Africa's acceleration. He was not able to continue it when he tried to take on Doug Bracewell in the same way but sliced him in the air where Worker juggled but hung on at backward point.
De Villiers picked up where van Wyk left off with a range of clean strokes: the one-handed cover drive, moving to a one-kneed loft over extra cover and the disdainful swat to cow corner. De Villiers was not his side's top-scorer but he was their game-changer because he put New Zealand's plans out with his combination of power hitting and precision placement.
When de Villiers holed out to deep midwicket just after halfway through South Africa's innings, they still needed 67 runs off 55 balls but there was never any doubt they would get there. Amla remained the anchor while Rilee Rossouw had some fun, sending Elliott over long-on, Adam Milne over long leg and McClenaghan over Ronchi's head. Rossouw's sprightly innings ensured South Africa won with 13 balls to spare and New Zealand were left wondering what it was they were supposed to do in the series opener.
Firdose Moonda is ESPNcricinfo's South Africa correspondent