I would be very surprised if Australia won that comfortably. However stranger things have happened!
This looks a very even match to me. Ireland should have the edge in the front row, but Australia has actually scrummaged ok in recent weeks. I feel the locking combo's are pretty evenly matched. Simmons has actually pretty good for the Wallabies this year, while Horwill has started to show some form over the last two weeks. O'Connell is still obviously class, and though I haven't seen a lot of Toner, he obviously has a bit of height! Australia may look to target Ireland at lineout time - Best can struggle at times, and Australia does have 4 excellent lineout options in Fardy, Mowen, Simmons, and Horwill.
I think Ireland have the advantage in the loose-forwards, with a more balanced combination and much better ball runners. Fardy and Mowen are hard-working players but don't offer much with ball in hand. It is somewhat ironic that Michael Hooper - by far the smallest member of the forward pack - is easily the most effective ball runner. The breakdown battle with be intriguing - it is not really an area where Australia have been as dominant as in recent seasons as Hooper is nowhere near as effective at Pocock in this area (though Gill could be a real threat off the bench).
The battle of the halves will likely have a big bearing on the result of the match. Genia as Cooper can be brilliant on their day, but Genia has been poor this year, and though Cooper has made some improvements (most notably in defense), he doesn't seem to be playing with the freedom he used too. Reddan and Sexton are probably much more consistent, and I feel Murray could be useful from the bench with his running game. I'm not sure how well Sexton has been goal-kicking, but Cooper has actually looked pretty good with the boot since he took over from Lealiifano.
I haven't seen a lot of Marshall, but I would give Ireland the edge in the midfield, though largely due to O'Driscoll. He may not be the player he once was with ball in hand, but he can still be a handful, seldom makes and error, and is rock solid on defense. Toomua and Kuridrani are starting to develop a handy combination in the midfield. They need to continue to work out there defensive patterns, but both do hit hard on defense, and offer a range of different skills with ball in hand. I feel the outside backs are pretty even. Cummins and Ashley-Cooper are both big strong players who give 100%, but aren't as elusive as some of Australia's wings in the past. In general I feel McFadden and Bowe fall into the same category (Bowe being probably the most elusive). Folau is obviously the key for Australia - they just need to get the ball in his hands. I expect we will see Australia will put a few high balls across to Folau on the wing - Bowe and Kearney are both excellent under the high ball if I recall correctly, but Folau is quite phenomenal in the air!
Overall I find it a hard game to call. For me it could go either way, but I picking Ireland to win close match, but maybe 5 points.