The Wallabies had looked to be coasting after Nick Cummins' second try in as many weeks helped them into a 22-3 half-time lead.
But Robbie Deans' men ground to a half after the interval as the Azzurri sensed a first-ever win against their southern hemisphere rivals.
Robert Barbieri dived over for a converted try two minutes after the re-start before a pair of Luciano Orquera penalties drew them to within three points with 25 minutes remaining.
But, despite some torrid play from the Wallabies, they held on to grab back-to-back wins on their European tour after their Twickenham success over England last weekend.
Australia handed scrum-half Brett Sheehan his first Wallabies start, six years after his debut, as the visitors looked to build on their 20-14 win over England last week.
They were well on course to do just that following the first quarter as they produced their best rugby of the game.
Orquera kicked over the first of his 14 points after three minutes but Berrick Barnes responded with a pair of penalties to send Australia ahead on 15 minutes.
Cummins then crashed over three minutes later to follow his first Wallabies try at Twickenham last weekend. The visitors set the ball through the hands before Kurtley Beale provided the final pass to send the Western Force winger over in the corner.
Barnes converted an added another penalty from near halfway as the Aussies went 16-3 ahead after 24 minutes.
Italy were in danger of being blown away as Beale then twice kicked over, the second after Barbieri saw yellow for slapping the ball out of Sheehan's hands.
But rather than roll over the Azzurri fought back and Orquera's penalty just before the break made it 22-6.
Barbieri then returned after half-time to immediately dive over and when Orquera added two quick penalties to a conversion they were suddenly just three points adrift with 25 minutes left.
Australia increasingly became sloppy under the Italian pressure but the hosts failed to make them pay, even when Digby Ioane was sent to the bin late on for tackling a player in the air.
- Sports & Recreation
- Robert Barbieri
- Luciano Orquera