The victory gave New Zealand an uncatchable seven point advantage over South Africa ahead of their showdown in Pretoria next Saturday
New Zealand boast 21 points, South Africa 14, Argentina eight and Australia prop up the table with five after five of the six matches in the tournament for the leading teams in the southern hemisphere.
Two weeks ago South Africa beat New Zealand 36-34 in Wellington to fashion out a chance of securing the title for the first time. But that opening disappeared when they failed to secure a bonus point in the 23-12 win over Australia in Port Elizabeth on Saturday.
That result left the All Blacks needing a win to secure the title and they outscored the Pumas by five tries to two to collect a bonus point as well.
New Zealand fly-half Beauden Barrett redeemed himself in the match against the Pumas. He was successful with all four of his conversion attempts. During the defeat to South Africa the 27-year-old playmaker missed four of six attempts.
"There are always things to iimprove but we won and that’s the main thing,” said New Zealand head coach Steve Hansen.
His Argentia counterpart, Mario Ledesma, highlighted New Zealand’s superiority in the scrum as the key to their win. “We’re 15 years behind them in terms of professional organisation,” he said. “They led us a merry dance in the scrum and they capitalised on their chances that came from that.
“But they did make mistakes and we were able to get something from them.”