Orquera made Australia pay for their many ruck infringements by slotting a couple of penalties in the second half to give him a personal tally of 14 points, while his late miss was his only unsuccessful attempt.
Italy peppered Australia's line throughout a frantic second period with Ben Alexander and Kurtley Beale coming up with try-saving tackles.
After scoring against England last weekend, Cummins' first-half try was only Australia's second of the tour and came after a simple shift to the right edge opened up space for the Western Force flyer.
Berrick Barnes slotted three penalty goals in the first half before Beale took over the kicking with the Australian fullback complaining of a tight groin.
Australia lost halfback Brett Sheehan in the 31st minute when his left leg was twisted awkwardly in a ruck and prop Benn Robinson left the field six minutes later after taking a heavy knock.
The Wallabies were reduced to 14 men for the final two minutes after winger Digby Ioane, who replaced Cummins in the 72nd minute, was yellow-carded for taking out a man in the air after catching a Beale chip-kick.
-AAP