Winger-turned-centre Keith Earls has handed a depleted Ireland a lifeline in their meeting with Australia.
Ireland led 17-0 in the first half after an impressive start, but by the start of the second 40 they had lost three starting backs - Rob Kearney, Andrew Trimble and Jared Payne - to injury.
A combination of an inexperience Irish back division and a significant improvement from Australia saw the Wallabies storm back into a 24-20 lead at the hour mark.
However, the introduction of flanker Peter O'Mahony appeared to be the catalyst for a mini-revival from the Irish.
The Munster man made a number of barnstorming runs before some good play saw Simon Zebo, who came on to replace Kearney after seven minutes, feed Earls who touched down in the corner.
Out-half Paddy Jackson, who has been imperious with the boot so far, added the extras to put Ireland 27-24 ahead.