The Wallabies will have to win in Sydney to seal their three-Test series against Ireland, the visitors levelling with a dominant 26-21 victory at Melbourne's AAMI Park.
The win broke a 39-year drought for Ireland, who last beat the Wallabies on Australia soil in 1979, also in Sydney.
Australia pulled back to within striking distance after a 78th-minute try by Taniela Tupou but Ireland showed why they were Six Nations champions in a clinical display.
Ireland made eight changes to the team after their first-Test loss in Brisbane, with five-eighth Johnny Sexton returning to partner star halfback Conor Murray and orchestrate the victory.
While the halves were dangerous all night, their powerhouse new front row and flanker Peter O'Mahony at the breakdown laid the platform for the win.
They starved the Wallabies of possession, with Australia managing only 43 per cent for the match, and nullified the aerial prowess of fullback Israel Folau which had worked so well in Brisbane.
The Australians couldn't have had a better start with centre Kurtley Beale running onto an inside ball from Bernard Foley only one minute into the game to leave the defence grasping at thin air.
But any momentum they had stalled when winger Marika Koroibete was given a yellow card after a dumping tackle on Irish fullback Rob Kearney.
Ireland kicked for touch and, from that lineout, started a rolling maul before Murray showed his smarts to send the ball wide to winger Andrew Conway, who scored where Koroibete would have been defending to level at 7-7.
As the visitors piled on pressure, the Wallabies looked flustered and their poor discipline proved costly, with Sexton kicking penalty goals to keep the scoreboard ticking over.
Australia's chances weren't helped when they lost veteran halfback Will Genia after 28 minutes with a wrist injury.
The Wallabies trailed 16-14 at halftime after being awarded a penalty try which led to prop Tadhg Furlong also given a yellow card for collapsing the maul.
Ireland pushed the scoreline out to 23-14 when they ran the Wallabies' defence ragged.
Winger Keith Earls was denied after 16 phases but, from the next lineout, Furlong planted the ball across the line.
Tupou took advantage of Ireland playing a man down to score after flanker Jack McGrath was yellow-carded, with the match coming down to a frantic finish.
But Ireland's rock solid defence again held up with Koroibete knocking on to end their hopes of an early series win.