The Black Caps have taken the second one day international against the Proteas, the first time New Zealand has won a one day series in South Africa.
New Zealand beat South Africa by 27 runs in the second One Day International in Kimberley on Tuesday, taking an unassailable 2-0 series lead with a final game still to be played.
An undefeated innings of 145 from Kane Williamson propelled New Zealand to 279 for eight.
South Africa looked on course for victory as they reached 165 for one after 30 overs but a collapse fuelled by five run-outs caused them to be dismissed for 252.
New Zealand captain Brendon McCullum told Sky Television it was a phenomenal effort for a 9th ranked team against the top side, and will go down as one of the Black Caps best ever one day victories.