West Indies took six Australia wickets for just 19 runs as the hosts secured victory in the sides' T20 opener.
The Windies put on 145-6 in St Lucia, where Obed McCoy and Hayden Walsh did most of the damage with the ball in an 18-run triumph.
Andre Russell's maiden half-century was also a telling contribution in what was a fifth win in six for the Windies against Australia in this format
Australia had looked in good shape after restricting the home side to 35-3 off 7.4 overs, but Russell's 51 came from 28 deliveries to help his side to a credible total.
The tourists lost the dangerous Aaron Finch in the second over of their response before rallying to reach 108-4 at just past the midway point.
With Australia firmly on track for the win, the Windies needed something special and it was McCoy and Walsh who produced the goods.
Wickets tumbled as McCoy took 4-26 and Walsh claimed 3-23, with seven of Australia's batting order limited to a single-figure contribution in an innings where they were all out for 127 in 16 overs.
THE REAL MCCOY
It was a devastating spell with the ball for McCoy, who accounted for Josh Philippe, Ashton Agar, Mitchell Starc and Josh Hazlewood.
But it wasn't just his wicket-taking that impressed, with McCoy suppressing Australia's run rate by delivering 13 dot balls in a man-of-the-match display.
"It feels great," said McCoy. "I've been working really hard. It was just all about execution and sticking to the team plan.
"Normally on that surface the ball has nice bounce and carry but I was just trying to mix up my pace as much as I can."
NO EXCUSES FROM FINCH
Australia captain Finch offered no excuses for what was a shocking collapse from his side.
Finch admitted his team needed to show a little more intelligence in their approach.
He said: "We've been working on trying to be a little more aggressive in the middle overs but maybe just need to rein it in and have some more smarts.
"I thought the wicket played a little better batting second. There's no excuses for our batting display there.
"You've got to dust yourselves off and come again with the same attitude but just execute a little bit better under pressure."