The Irish have played creditably over the past fortnight, losing narrowly twice in two Tests against the All Blacks.
Coach Eddie O'Sullivan was disappointed his side missed two chances to beat New Zealand for the first time in 101 years of competition but is hugely encouraged by their displays.
He said: "It has been a very productive tour for us and the players have got a lot out of it.
"We had two games that were there for the taking and that was disappointing, but it is not easy winning down here and they were two very good performances."
Ireland will now go into their clash with the Australians at the Subiaco Oval in Perth with confidence.
The Wallabies have only ended a recent run of poor form with back-to-back victories over England in the past two weeks.
O'Sullivan is keeping faith with British & Irish Lion Ronan O'Gara for the match after the fly-half was blamed for the defensive lapses which cost Ireland in the second match against the All Blacks.
The only change to the team comes at full-back with Geordan Murphy dropping to the bench to allow Girvan Dempsey to win his 66th cap.
Australia fly-half Stephen Larkham is bracing himself for a difficult contest.
Larkham said: "It's definitely the best Irish side I've played against over the past 10 years.
"Not just because of the form they've shown over the past couple of weeks but because of the quality of player they can put on the field.
"They've picked a very mobile forward pack, a forward pack that will get across the ground very well."