Johnson Charles' 57 helped the Windies to an imposing 191 for six before an under-strength Australian side stuttered in pursuit. Adam Voges' quickfire half-century gave the hosts hope but when he, and Shaun Marsh, were run out midway through the innings Australia needed more than 10 an over to win.
Brad Haddin briefly threatened to meet that, swiping 19 from one Narsingh Deonarine over, but the Windies bowlers kept calm to secure victory in the one-off match. Keiron Pollard was the pick of the bowlers taking three for 30 as Australia finished on 164 for eight.
Debutant seamers Nathan Coulter-Nile and Josh Hazelwood were quickly under pressure as the Windies batsman made a flying start. After Chris Gayle's latest failure - the opener survived the simplest of drops from Haddin only to make eight - Charles and Darren Bravo set the foundation for a big score.
The pair put on 88 in 55 balls with Charles, fresh from his century in the fifth ODI, reaching his half-century with an array of unorthodox shots. Coulter-Nile eventually got him to chop a slower ball onto his stumps and while Darren Bravo was run out soon after, following a mix-up with Pollard, the Windies accelerated towards 200.
James Faulkner, three for 28, attempted to slow their progress, removing Pollard and Dwayne Bravo in the 17th over, but Andre Russell blasted an unbeaten 23 from 11 balls. The all-rounder and Deonarine took 17 off Coulter-Nile's final over.
Australia's chase began badly when out-of-form opener Aaron Finch chopped on before Perth Scorchers pair Marsh and Voges steadily attempted to lay a winning platform in a 74-run stand. Voges was more fluent, reaching his half-century off 31 balls, while Marsh was seemingly gathering himself after reaching 21 from 19 balls.
But any assault was circumvented when Marsh was caught short by Tino Best's throw from point before wicketkeeper Devon Thomas ran Voges out in the next over attempting to steal a single.
With more than 10 an over required Australia's new men to the crease needed to hit the ground running. George Bailey and Haddin initially did just that with the wicketkeeper twice clearing the mid-wicket rope in Deonarine's expensive 14th over.
But Haddin was out in the next from Pollard, when a diving Russell held on well in the deep, leaving the Australian tail with too much to do.