The result means New Zealand, who will host the British & Irish Lions in 2017, are guaranteed to finish first having established an unassailable six-point lead over South Africa.
And captain McCaw, who matched Sir Colin Meads' record of 133 games for the All Blacks, is confident his side will cap their Rugby Championship campaign with victory against the Springboks in Johannesburg next weekend.
"It's nice not to have to worry about bonus points or different permutations against the Springboks," he said.
"They were lovely conditions to play in and I'm really proud of the way the guys took their opportunities.
"The Pumas came to play as well and I think it was a pretty good match to watch but I'm proud of our guys because we took our chances.
"We defended really well and didn't let them over until the last minutes of the game - that shows the backbone of the team."