In theory he'll be able to do what he always does and breeze into action and make test football appear to be ridiculously easy. But he knows this week is different.
"As much as you would like to say no, it is definitely, yes, because you are there, you are doing it and you are driving the team from the start," he says.
"Whereas when you are in the reserve team you are sitting back a little bit. You are getting the detail but you are not probably driving the game as much. I guess it is a little bit more intense this week. But that is to be expected.
"It is a great opportunity for me to play in my preferred position and get a start. It can't come around quick enough."
Expectation is the beast that Barrett will battle with most. As an All Black, he's used to handling public scrutiny - that's not the hard part. It's dealing with his own expectation that will be tough.
He's waited what must feel like an age to wear No10 and with, arguably, the two best first-fives in world rugby ahead of him, it is understandable that he'll want to make an impact.
It is understandable that he'll want to impose himself, showcase what he's got and try to establish that the gap between him and Aaron Cruden and Daniel Carter is bridgeable.
And yet, the worst thing he could so on Saturday is overplay his hand. He doesn't need to take too much on. He doesn't need to deliver 80 minutes of wow. A controlled, measured accurate performance where he sticks to the basics and sticks to the gameplan - that's what will impress the selectors.
"I have got to try to stay calm and understand that I just need to do my job," he says. "I don't have to make a huge impact. There are plenty of good players around me."
Conditions aren't forecast to be great on Saturday night, with rain expected and Barrett's perhaps fortunate that the All Blacks have recent experience to draw on in regard to traps they have to avoid.
When they encountered a filthy night in Sydney a few weeks back, the All Blacks were reactive and tentative. They sat back and expected things to happen and as coach Steve Hansen would later say, their entire structure collapsed.
It was a collective meltdown, but as always, much of the responsibility lay with the No10 and Barrett knows he'll be the man who has to ensure the All Blacks actively take the game to Argentina.
"I think it affected our general skills. We didn't back our skills and we didn't execute what we wanted to. We didn't get the ball to wide channels or play in space. That's why we put a lot of emphasis on that in Auckland. It is going to be a little like the Sydney game this weekend I feel - testing conditions - and we have to back our skills."
