The Blitzbokke were clinical at the breakdown and ran away with a 26-17 win to claim their second tournament in succession after winning in Dubai last weekend.
The win sees South Africa go to the top of the series ladder with 59-points, eight ahead of Fiji who were upset 21-14 in the Plate final by the USA.
New Zealand leap-frog Australia into third place with 47 points after the Aussies (46-points) finished in third place by beating Argentina.
Canada were too strong for Kenya in the Bowl decider, taking a 24-5 win in a replay of the Dubai Shield final last week.
Portugal claimed some silverware by upsetting Gold Coast finalists Samoa 19-14 in the Shield final.
New Zealand had only conceded two tries in five games in an easy run into the finals, beating the USA 28-7 in the quarter-finals and Argentina 29-0 in the semis.
South Africa were similarly impressive in the group stages and finals, thrashing the USA, Kenya, Wales and England through to the quarter-finals before beating Australia 19-10 to reach the decider.
Sherwin Stowers opened the scoring for New Zealand in the final with an overlap on the left but a well-taken quick tap saw South Africa’s Philip Snyman level it up soon after.
The Blitzbokke hammered each breakdown, putting pressure on New Zealand possession and Cecil Africa pounced from another quick tap penalty for a 12-7 lead for the hosts.
South Africa’s breakdown tactics turned against them when they gave away four ruck penalties in a row after the halftime siren as Africa was sent to the bin and the Kiwis grabbed a try and a 12-10 score-line at the break.
Speed demon Seabelo Senatla turned on the after burners in the second spell and Africa kicked a sideline conversion for a 19-10 advantage before Joe Webber finished off a nice move under the posts to bring the gap back to two.
The decisive play came three minutes from fulltime with another South African turnover and some brilliant offloading for a try on the right and a 26-17 advantage which they maintained until the end.