Led by an unbeaten century from Wavell Hinds (125*), West Indies on Friday handed a second consecutive defeat to Australia when they successfully chased 253 runs with three wickets to spare at the Queen's Park Stadium in Grenada.
Hinds, adjudged man-of-the-match, slammed six sixes and four fours as the Windies reached the target in the 49th over.
Australia now lead the seven-match series 4-2.
Earlier, Australia won the toss and elected to bat. Openers Adam Gilchrist and Mathew Hayden looked in total control against the pace of Mervyn Dillon and Corey Collymore; they added 90 runs in the first 14 overs.
Hayden (29) finally lofted a leg-side flick off Collymore into the hands of Hinds just short of the square-leg boundary.
West Indies' battery of off spinners then put the brakes on.
Australia skipper Ricky Ponting gifted his wicket when, on two, he pushed the ball to Brian Lara at mid-on and was easily run out.
Gilchrist, who hit four fours and two sixes, then sliced the next ball from Marlon Samuels to Lara at backward point.
The wickets continued to fall as Andrew Symonds (16) miscued a Ramnaresh Sarwan spinner to give Lara another catch at mid-on while Darren Lehmann was caught and bowled by Chris Gayle after scoring 43. Brad Hogg, looking to guide a ball to third man, opened the face and was caught second ball at slip off Samuels without scoring.
Gayle, with another caught and bowled, got rid of Jimmy Maher (19) as the batsmen continued to struggle with their timing.
Brett Lee and Andy Bichel, however, put together a 50-run stand for the eighth wicket, Bichel continuing his excellent series by hitting two fours and a six off successive balls from Sarwan as 17 came off the over.
Bichel scored at a run a ball before hitting out at Gayle and being caught in the deep by Lara, who took his third catch.
Australia were dismissed off the last ball as Nathan Hauritz was run out by a throw from the deep.
It was the first time in the seven-match series that Australia had been bowled out.
