A late flourish from James Franklin has helped New Zealand set South Africa a competitive total in their third ODI in Potchefstroom.
The 32-year-old struck 53 from 52 balls to help the Kiwis to 260-9, while Grant Elliott and Colin Munro also reached half centuries.
Lonwabo Tsotsobe and Ryan McLaren did the damage with the ball for the Proteas, both medium pacers finishing with four wickets apiece.
South Africa cannot win the series as New Zealand have a 2-0 lead in the three-match series.
