In Yokohama, they looked more assured playing their way out of their own half with McKenzie providing that second clearance kicking option.
They made fewer rushed and frantic decisions in the Wallabies half, partly down to a more measured mindset but also because McKenzie was on hand when Barrett wasn't around to invariably make the right call on what to do.
But it was maybe the intangible impact of McKenzie that was most valuable; his presence from the start seemed to release some weight from Barrett's shoulders.
In the two tests against South Africa, he struck a lone figure trying to cope with all the tactical direction in the face of a dominant Springboks defence. He played like a man who was burdened with too much responsibility.
Against the Wallabies, though, he had a greater sense of mental freedom about him.
He was more certain in his movements, more decisive with the ball, and as a result, he generated more flow in the All Blacks' attacking game.
He looked to have more space, more time and perhaps more confidence.
"Walking off the field, I said it was great having him out there," Barrett said in response to McKenzie's contribution at fullback.
"His chat was really good and I always felt there were more options; there was a kicking option and I felt a lot easier in our own half knowing there was a genuine kicking option out there. It is something we have to grow among all our backs - kicking being an option.
"It was just such a positive to have him out there, as we are all aware of his attacking potential."
The coaches made no secret of their delight at the way the dual strategy worked - particularly in how effective it was at keeping the Australian defence on the back foot.
When the All Blacks have been beaten in the past two years, it has mostly been against teams who have generated ferocious line speed and smothered the All Blacks' attack at source.
The Springboks did that for much of the test at Loftus Versfeld and it meant the All Blacks couldn't get much going with ball in hand until the final 15 minutes.
They don't want to be bystanders for that length of time in any test and they feel the arrival of McKenzie at fullback has given them more weaponry to challenge opposition defences and make them think about the risks they could be taking by charging off the line.
"He's a quality player. We were really happy with the options he gave us because that took a bit of pressure off Beauden," said Hansen of McKenzie. "So having two drivers on the park is good for us and something we will look to keep doing."
The question that pops up now is when will Naholo be seen in a big test again?
Rieko Ioane and Ben Smith were outstanding and the balance of the back three looked spot on.
How Naholo's power game fits into the picture is increasingly hard to see, and as he's not quite equipped to be a serious option to cover the midfield, a spot on the bench isn't likely.
Jordie Barrett will most probably feature against Japan and Italy and then be told to head back to the Hurricanes and work on his kicking game and decision-making to build them to the point where he could be considered a second playmaker.
