An error-strewn first half from Jacques Brunel's side saw the Wallabies take a commanding 19-point lead, but Italy reduced the deficit just before the break and a spirited comeback saw them shut out Australia in the second period.
Italy even had chances to take the lead as it went close to recording its first victory over Australia in 15 meetings.
Robert Barbieri - who was earlier yellow carded - scored the try for Italy, the first of 13 points in 15 second-half minutes for the Azzurri.
Nick Cummins turned over for Australia.
There was a long delay 15 minutes into the second half following a serious injury to Mirco Bergamasco, who was taken off on a stretcher.
