Potchefstroom: James Franklin battered a late half-century to lift New Zealand to 260 for nine in the third one-day international on Friday, raising the visitors' hopes of inflicting a historic first home series whitewash on South Africa.
Tsotsobe struck twice early to get Martin Guptill and Kane Williamson in his four wickets for 45, but New Zealand recovered with successive half-century partnerships between Grant Elliott and Colin Munro and then Munro and Franklin.
Munro's maiden half-century, a 57, and Elliott's 54 helped to hold together New Zealand's innings after the Black Caps were 68 for four and 129 for five.
New Zealand leads the series 2-0 and can become the first team to sweep a one-day series in South Africa ' a significant turnaround after they lost both Tests.
As good as South Africa were in the Test series, the Proteas have been left trailing by a canny limited overs effort from the New Zealanders, who continued to out-manoeuvre the home team in the final game of the short series.