Morne Steyn followed his conversion by scoring a penalty, just before Jaque Fourie's try on the half-hour mark. Steyn's inconsistency continued as he then missed the conversion, missed a penalty, but scored again on his fourth of the game.
Steyn got off to a better start in the second half by converting Frans Steyn's early try. He then converted his own on the hour mark.
South Africa's Tendai Mtawarira and Danie Roussouw's tries in the final 20 minutes, both converted by Steyn, then put the defending champions completely out of reach.
South Africa will next face winless Namibia on Thursday, September 22 in Auckland.