The victory owed much to a moment of madness from Australian prop Sekope Kepu who was red-carded just before the interval for a dangerous shoulder charge at a ruck.
The Scots had to overcame the loss of Stuart Hogg who was injured in the warm-up. Byron McGuigan came into the team with Sean Maitland switching to full-back. Ruaridh Jackson was called onto the bench.
After the game Gregor Townsend said: "It's an amazing result, to score so many points against the number-three team in the world.
"Obviously you have to take into account the red card. They were playing well at the beginning of the game, and came back at the start of the second half, but we just kept that mindset of wanting to play and working very hard and it got its rewards."
The Scots' points tally and margin of victory eclipsed the previous benchmarks in this fixture, with Hogg's replacement, Byron McGuigan, touching down twice on his first Test start.
The emphatic triumph brought down the curtain on Scotland's trio of autumn Tests, following a breathless win over Samoa and a narrow defeat by world champions New Zealand last weekend.
Head coach Townsend, who has now overseen home and away victories over Australia, says his players' ability to overcome the pre-match loss of Hogg proved their character.
"It probably says two things - we've got good depth just now, Byron McGuigan was outstanding on his first start, and it also says this team are resilient," Townsend told BBC Sport.
"They showed that last week against New Zealand when they were dealing with injuries, and dealing with something just before kick-off didn't knock them off their stride.
"It wasn't perfect, the more the game became unstructured suited us and the fact we had a one-man advantage."