Australia extended their lead with a Giteau penalty in the 54th minute after he'd missed a relatively easy one earlier as the visitors dominated the third quarter.
However, Ireland received the boost they so badly needed with a Tommy Bowe try in the in the 56th minute and although Australia regained the lead witha Rocky Elsom try that Giteau brilliantly converted from the touchline, the home side ended the game the dominant side.
Bowe got over the line with two minutes remaining only for the video ref to rule it out but from the subsequent five metre scrum, Tomas O'Leary's superb cut-out pass gave his skipper a free run to the line.
IRELAND: Rob Kearney; Tommy Bowe, Brian O'Driscoll (capt), Paddy Wallace, Luke Fitzgerald; Ronan O'Gara, Tomas O'Leary; Cian Healy, Jerry Flannery, John Hayes, Donncha O'Callaghan, Paul O'Connell, Stephen Ferris, David Wallace, Jamie Heaslip.
Replacements: Sean Cronin, Tom Court, Leo Cullen, Denis Leamy, Eoin Reddan, Jonathan Sexton, Keith Earls.
AUSTRALIA: Adam Ashley-Cooper; Peter Hynes, Digby Ioane, Quade Cooper, Drew Mitchell; Matt Giteau, Will Genia; Benn Robinson, Stephen Moore, Ben Alexander, James Horwill, Mark Chisolm, Rocky Elsom (capt), David Pocock, Wycliff Palu.
Replacements: Tatafu Polota Nau, Matt Dunning, Dean Mumm, George Smith, Luke Burgess, Ryan Cross, James O'Connor.
Referee: Jonathan Kaplan (South Africa)
Assistant Referees: Christophe Berdos (France), Andrew Small (England)
Television Match Official: Geoff Warren (England)