South Africa 357 for 4 (van der Dussen 133, de Kock 114, Miller 53*, Southee 2-77) beat New Zealand 167 (Phillips 60, Maharaj 4-46, Jansen 3-31) by 190 runs
Pune: South Africa are on the brink of clinching a World Cup semi-final berth after a 190-run thrashing of New Zealand in Pune on Wednesday.
Rassie van der Dussen made a superb 133 and Quinton de Kock hit his fourth century of the tournament in a 200-run stand as the Proteas posted 357-4.
New Zealand then slumped to 167 all out, with Keshav Maharaj taking 4-46.
Victory returns South Africa to the top of the table while New Zealand drop to fourth after a third straight defeat.
Stand-in New Zealand skipper Tom Latham opted to bowl after winning the toss, allowing South Africa to play to their strengths and put a big total on the board.
Temba Bavuma's side took the same approach as they have throughout this tournament, starting steadily before accelerating rapidly late in the innings.
After Bavuma fell for 24, De Kock and Van der Dussen laid the foundations, each batting with great control and making the most of New Zealand dropping tough chances to remove them on their way to three figures.
De Kock went past 500 runs for the tournament in the process, becoming the first South Africa batter to reach that milestone at a World Cup, before he fell for 114 off 116 balls. Van der Dussen reached his century off 101 balls then kicked on brilliantly.
New Zealand's task was made harder by a hamstring injury to seamer Matt Henry, who will have a scan on Thursday to assess the damage, allowing David Miller to smash four sixes in his 53 off 30 against a depleted attack.
Marco Jansen, who claimed 3-31, and his fellow fast bowlers did the initial damage to reduce New Zealand to 67-4 in reply, before left-arm spinner Maharaj hammered home South Africa's dominance as the Kiwis collapsed to 110-8.
New Zealand's only real resistance came through Glenn Phillips' defiant half-century when the game was already lost.
South Africa's place in the top for is now all but assured, with the Proteas batting and bowling units both impressing once again.
However, the injury-hit Black Caps find themselves in a battle to progress, with crucial matches against Pakistan and Sri Lanka to come.