If the All Blacks lose on Saturday after their disappointing 27-19 defeat in Sydney last weekend, the Australians win back the old cup they haven't held since 2003 and the world champions enter their Cup defence on successive defeats.
The significance of the test is obvious and it was All Blacks midfielder Ma'a Nonu, missing from the ANZ Stadium defeat due to a shoulder injury, whom today described his team as "out-passioned" in terms of the Wallabies' work on defence and at the breakdown.
"I thought they played well defensively, their kicking game was good as well and just their desire to get into the game physically [was impressive]," he said. "It showed the boys how passionate they were. I think we were out-passioned.
"I don't think we can hide away from what we saw at the weekend. If you look at how the Australians flew into those rucks, how they were physical, and just the way they played, everyone can see that."
Nonu will likely get a chance to help his team make amends after recovering from the niggle picked up in the narrow win over the Springboks in Johannesburg. And with Sonny Bill Williams due to miss the test with a gluteus injury, Nonu's imminent return is timely.
It's not only brute force that is required, although a bit more of that from the forwards would be helpful. The Wallabies went into the game apparently knowing exactly how the All Blacks were going to play, and Steve Hansen's men must return the favour.
David Pocock and Michael Hooper are likely to team up again in the loose forwards and the rushing outside-in defence of the Wallabies shouldn't provide as much of a surprise factor.
No.8 Kieran Read said a smart response was required, along with some old-fashioned brutality.
"We felt there were opportunities out there but if you don't hold the ball and look after it then you're not going to create any pressure," he said.
"It's not a given because they've got some great players ... so we've got to be smarter; just bounce back and be who we are, we're a good quality side so we've got to show it."
Nonu added: "It hasn't been a fun two days in terms of reviews, but we've just got to be confident in ourselves and have self belief.
"It's exciting. These are the games you want to play - it's tight and there are a lot of expectations. They beat us in the weekend and it's going to be one of those games with nerves from both sides. It's going to be one of those crucial matches.
With a narrower than expected victory over Manu Samoa, a solid victory over Argentina, a last-gasp win over South Africa, and now a loss to Australia, the All Blacks have yet to put in a compelling performance worthy of world champions and that is something Read and his teammates are keenly aware of.
"We want to go out there and perform well which we perhaps haven't done as a unit this year. We want to get our performance up and I think there are some key areas that we can improve which will markedly change how we're going to play this game."
