Ireland boss Schmidt can come out on top in battle of tactics
We will know sometime this afternoon what players will represent their national teams for Saturday's eagerly-anticipated clash. This one more than any will come down to the team dynamic. Players play but the conductor's baton in this Test is of rudimentary importance.
Joe Schmidt and Michael Cheika are the best coaches in the world. The talent available to both is pretty evenly matched, so whichever coach can eke out an extra percentage here or there will likely win.
The dreadnought versus the dispassionate - a fascinating clash.
No more than five years ago we had a confederacy of dunces in charge in European rugby.
The last of those, Scott Johnson, was 'moved upstairs' at Murrayfield.
Vern Cotter came to Scotland this season and suddenly the Jocks look competent and will unquestionably improve, but really all we have is coaching orthodoxy - competent coaches with the fundamentals of a game-plan and no more.
Stuart Lancaster has pulled the English back from the abyss and given them structured order and has re-established a sense of worth and common purpose, but it seems that is as far as he can take this team.
Warren Gatland too is struggling in Wales and needs to be competitive against the All Blacks on Saturday.
I don't think they will bother New Zealand too much out wide, and you feel that Gatland doesn't have too many more rabbits to pull out of the hat.
I have to say that I admire Cheika's methods and achievements.
He took two under-performing franchises in Leinster and the NSW Waratahs and led a radical turnaround in their outlook and demeanour and ultimately brought success in the Heineken Cup and Super XV.
The best index to a coach's character is how his team plays and Australia will, I am certain, start playing a determined and smart brand of rugby underpinned by a remorseless spend of effort.
It might just not happen this quickly on their four-match tour.
As with Schmidt, there will be no compromise.
Both coaches won't handicap their players' path to the World Cup by making lives easy. Better coaches demand more - belief in the game-plan is only half of it.
The Waratahs opportunity was an offer Cheika couldn't refuse.
The Queensland Reds and the Brumbies had been serially competitive and had won the Super Rugby competition several times each, yet Sydney and New South Wales had won nothing despite having both the talent and money. The comparison with Leinster was just irresistible.
Cheika's frustrations boiled over as the Waratahs' habits refused to yield to the new regime.
We could probably guess what Schmidt's state of mind was after his first match last November in charge against the Wallabies when Ireland's defensive effort retained all the properties of a kitchen colander.
Four tries and a thumping from a Wallabies side that played with measured abandon and confidence under Ewen McKenzie's tutelage.
McKenzie's ignominious departure before term probably caught Cheika short, though the Wallabies job was always the eventual target, but the unexpected change in direction will galvanise him and Australia will be a very decent side when they come back in 10 months' time.
Whether they will play like a decent side on Saturday depends a lot on what Cheika does in selection. If Quade Cooper and Kurtley Beale are picked it will add spice - two jokers who if they act up again will have their careers ended by Cheika.
Australia have been heavily reliant on Israel Folau for progress out wide and I think he has struggled because currently none of his inside players can unlock his talent to the full.
Cheika will eventually get his best team on the pitch and make them click.
It didn't take Schmidt too long to impose his ideals and so we suspect that Saturday will be very close as these two 21st century Merlins weave their magic - both men a cut above on the international coaching stakes.
Savour this one, it will be a high-stakes game to remember. Cat and mouse between two driven men - Schmidt to shade it in the second half.