A successful series may grant the impetus to gain another two years while failure could spell the end of the road.
Co-coaches are always strange beasts. John Hart and Alex Wyllie were a disaster in 1991 but the trio of Graham Henry, Steve Hansen and Wayne Smith (not strictly co-coaches but Hansen and Smith have long histories as head coaches) have been extremely successful.
McKenzie played down any notion of international ambitions: "People like to speculate but I'm not looking for a job. I've got a good one, that's that," he told Australian media. He may yet be persuaded but appeared to discount chances of a possible alliance with Deans, brusquely commenting, "You don't have two CEOs at a company."
Meanwhile, Farr-Jones hopes the review into Australa's World Cup takes a measured view: "It hasn't been great but at the end of the day we got beaten by a much better team," says Farr-Jones. "There were guys that didn't turn up but they gave it their best shot. We were brave, gutsy and courageous. While we were hopeless with ball in hand against New Zealand, you would not have seen a more committed display in world rugby than against South Africa in Wellington."
Farr-Jones adds that sometimes the role of the coach, and conversely the blame or credit, can be over-emphasised.
"Sometimes we can over-elevate coaches - and other times we can underrate them," says Farr-Jones. "You can only work with the cattle that you have got. Sure, they are responsible for getting the cattle but only the cattle can do the job in the 80 minutes. Look at Marc Lievremont - by all reports he is doing nothing with France and they are in a final. They have only played 40 minutes [first half vs England] of good rugby the entire tournament."
Deans has a mixed record since 2008. He has brought on a new generation of talent that should be a force in the coming years. His team turned the tables on South Africa after historically struggling there and had some recent success against the All Blacks, as well as winning the Tri Nations for the first time in years.
Against that have been some inexplicable losses, especially to moderate Northern Hemisphere sides on end of year tours.
It means his overall record is significantly worse than that of former coaches like Rod McQueen, Bob Dwyer and Alan Jones - though Deans has had to deal with an expanded Tri Nations and no coach has faced off more against the All Blacks in such a short space of time.
Another black mark was the Wallabies, failure to bring their brand of running rugby to this World Cup - they managed just one try in their three big games against Ireland, South Africa and the All Blacks.
Speaking after their win over Wales on Friday, David Pocock and Berrick Barnes hope the Australian reaction will not be too harsh. "I hope things are kept in perspective," said Barnes, man of the match against Wales."Obviously we are disappointed - we came here to win the tournament but there was no lack of effort.
"We were beaten by a better team on the day and I think after Sunday people will realise how good this All Black team is."
Said Pocock: "Of course there is going to be some negative reaction.
"People back home had high expectations and ultimately they haven't been fulfilled. But we can take plenty of positives out of this tournament - especially the performance against South Africa."
