Coach Steve Hansen, however, then went to his bench earlier than expected and the home side scored five unanswered tries to earn their third successive bonus point victory after two comfortable wins over Australia.
"It was a real test match, we really had to work really hard for it," All Blacks captain Kieran Read said in a pitchside interview.
"We certainly came out with some intent and they matched it, and that's exactly what you want, games against quality sides. It was a good game."
Unlike two weeks ago when the Wallabies seemed more intent to spoil the game rather than play it, the Pumas took the home side on, with Facundo Isa, Pablo Matera and Agustin Creevy driving through the middle and then stretching them out wide.
Their high tempo, possession-based approach also ensured they did not allow the All Blacks to counter attack as the home side found themselves under immense pressure and gave away numerous kickable penalties.
Flyhalf Nicolas Sanchez slotted four penalties, while winger Santiago Cordero finished off a beautiful movement early in the first half.
The All Blacks, however, looked just as dangerous when they did get their hands on the ball with Julian Savea, Barrett and Ben Smith all crossing for first half tries, which the flyhalf converted while Israel Dagg slotted a long-range penalty.
Sanchez narrowed the gap 10 minutes into the second half with another penalty but Barrett and the bench then took over as the injection of fresh blood upped the intensity.
"That bench was outstanding for us," Read added. "We've got a squad of 32 who can come on and do a job, the 23 was needed... and they did a great job."
Barrett used his pace to twice break the line and put Ryan Crotty over before Charlie Faumuina finished off a team try sparked by the flyhalf inside his own half to blow the score out to 38-22 with quarter of the game remaining.
Crotty and Ben Smith both added their second tries before Luke Romano crossed to give the All Blacks a scoreline that flattered the home side.
(Reporting by Greg Stutchbury in Napier; editing by Sudipto Ganguly)
