Flyhalf Beauden Barrett and the replacements sparked the home side, scoring three converted tries in 10 minutes to end the game as a contest after Nicolas Sanchez's fifth penalty had reduced the deficit to 24-22 for Argentina.
"I think we might have been reading our own press the way we played that first half," Hansen said. "The frustration we copped in that first half will be good for us because we will go away and learn that we need to prepare properly and turn up properly.
"They're a young side and there are going to be times when they hit road bumps and we hit one... and we came through it the other side.
"If we had struggled the entire game then I would have been more frustrated."
The All Blacks had not really been tested by Australia in their first two Rugby Championship clashes, with the Wallabies blown off the park in Sydney before they adapted a spoiling game plan in Wellington two weeks ago.
On Saturday, however, the Pumas showcased how far their game has come since they were admitted to the Rugby Championship in 2012, with an aggressive forward performance supported by a wide game with the ball in hand.
In the first 50 minutes, they put the world champions under immense pressure and their opening try to winger Santiago Cordero cut the vaunted All Blacks defence to shreds with change of angles and willingness to attack around the fringes of the ruck.
"We probably just let them get a flow on around that ruck, they picked and goed and got in behind us and we probably let the game drift a little," All Blacks captain Kieran Read said.
"We're proud of the way the guys stuck at it, sometimes when it gets tight, we probably haven't been in that situation as a group, so plenty of (lessons) from that."
(Reporting by Greg Stutchbury in Napier; Editing by Sudipto Ganguly)
