Where is the tipping-over point at the MCG tonight?
In other words, should events turn horribly wrong for either side - through injury, scoreline or performance - has a World Cup campaign suffered a significant setback?
Games like this have split personalities, depending on where interests are vested.
The promoters will claim a momentous transtasman battle, with tickets prices to match at up to A$95 ($116) a pop.
Rory "The Story" Fallon apart (and bless him for putting angst into proceedings), the combatants have played down any major consequences, with even Ryan Nelsen saying the result is not paramount.
Imagine, though, the reaction if the All Whites win by four goals - a glorious night was had by Kiwis one and all.
Imagine if they lose by four goals - the result didn't matter and they learned a lot.
The team most likely to win by four are 20th-ranked Australia - New Zealand are in the high 70s.
So, in theory, Australia have most to lose.
The All Whites have plenty at stake, however. They won't want to head to their Europe camps and games on a big loss, nor suffer key injuries.
Thanks largely to Nelsen, whose impact allows guarded optimism there might be one good day in South Africa, the All Whites have wowed the public, but football games aren't won on the 6pm news.
Not everything ran smoothly, despite soccer embers being stoked so encouragingly. There have been underlying tensions.
Just a lazy look will find a strange schism between the team and the NZF executive - they include a spat involving assistant coach Brian Turner and NZF chief executive Michael Glading over the NZFC's standards, twisted talk about Ricki Herbert's post-World Cup prospects and anger at NZF's failure to appeal against the Glen Moss suspension. Limelight has been uneasily shared.
Soccer is a world of intrigue, and bizarre as this may seem, since the World Cup could change everything, there are strong rumours that Herbert believes Glading wants him out.
The cohesive warmth and charm of 1982, when Charlie Dempsey, the game's supremo, and coach John Adshead plotted soccer's way into the nation's heart, is missing.
Centre stage, but with a curtain ever down, is Herbert, a man who sleeps far easier than he excites the public.
There is hardly a line on his 49-year-old face, and he delivers few verbal ones to remember.
Herbert will only draw warmth, and attention for soccer through the power of his record, as he began to do at the Phoenix, where his team had brilliant end-of-year contests and set the game on a new path. His club signings have been particularly inspired.
Adshead-like he is not. Herbert is undemonstrative and guarded. Perhaps you are either with him or against him, and might easily go from one to the other. A bit of a public riddle, our Ricki.
His burst of emotion after the All Whites qualified by beating Bahrain in Wellington was so out of character that it was like watching monastery gates part so Hugh Hefner could charge out.
You can only wonder what the World Cup pressure will do, and whether he has the ability to inspire at that level. This characteristic is still vitally important if you look around the world's most successful managers.
Not all of us celebrated uncontrollably late last year.
Buried in the hoopla were adequate, goal-challenged performances against Bahrain laced with good luck, plus an earlier defeat against Fiji.
There is a real affection for these All Whites around the country, but also a lot of dancing in the dark.
Our soccer players do have some leeway. We hang the All Blacks for false words, but don't hang on every All White word. Led by Nelsen's battle cry, the players have set very high standards for their World Cup, but much of the public won't hold them to these.
A credible World Cup is vital, however, for a game with dreams, Fifa millions about to arrive in the bank, and a determination - as NZF chairman Frank van Hattum put it to me - that not a single dollar is wasted.
As for tonight, the quality of the contest is extremely important especially as we hardly ever see the All Whites in major, or even minor, battles.
Australia v NZ
* Melbourne, 9.30pm
* SkySport 2
Soccer: The big questions for Herbert
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