I see a comfortable win for the Aussies. Probably the best backrow combination with Pocock, the best openside flanker in the world IMHO, Fardy a good test level player and the big dog, Ben McCalman, perhaps the best ball carrier at 8 ATM in Australia.
A couple of centres with no experience at this level for the Pumas side (Socino-Moroni) against a solid couple as Toomua-Kuridrani, both top class player.
If Holmes can keep his performance at the scrum of the last week, Australia shouldn't have problem at the scrum. Also, Hooper as impact player in the last 20 minutes with tired legs will be a LETHAL weapon.
The only chance for the Pumas is using the South African style, pick and go with the piggies and try to dominate the Wallabies tight-five.
It also depends about the advantage that the Aussies can make in the first 60 minutes. QC and KB as back-ups in the last 20 minutes don't guarantee safety on defense. If Cheika picks both at the same time, the Wallabies backline will become weak in defense