In another clinical performance, Australia amassed 5-324 and had the game as good as won before twilight, as West Indies skipper Chris Gayle was out to Doug Bollinger for the fourth time in four completed innings this series.
Gayle top edged two sixes but was out for 14 in the third over, and the tourists were all out for 199. Bollinger finished with 3-33.
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Australia's win kept them on track for a first unbeaten season in nine years, and secured a 4-0 series win after the third game was washed out.
Ricky Ponting's side has now won 24 of its past 29 matches, with two no-results.
But not even that excellence could sway many fans to watch in glorious weather, as a paltry crowd of 15,538 was doubled by the attendance at the AFL pre-season game between Collingwood and St Kilda at Etihad Stadium.
Crowd numbers down
Crowds have been down at the one-day cricket this season, but Friday's attendance was the lowest for an Australia-Windies game at the MCG, and Cricket Victoria chief executive Tony Dodemaide admitted it was disappointing.
"We would have liked it to have been more but we understood it was going to be a bit of a challenge today, given the nature of the series and the fact there are other options with the football on down the road," Dodemaide told AAP.
Australia's batsmen did their bit to entertain, as Shane Watson (51) and Brad Haddin (32) smashed an opening stand of 81, skipper Ricky Ponting stroked 61 and James Hopes (57 not out) and Adam Voges (44 not out) cut loose at the death.
Hopes walloped a half-century in 24 balls - the fifth-quickest by an Australian batsman - and his knock included 10 fours and 19 from one Ravi Rampaul over.S
Shoddy fielding
Australia benefitted from shoddy West Indies fielding, as five catches went down.
Haddin had two lives in the fourth over, Wavell Hinds dropped a sitter at long-on when Hopes was in full flight, and the tourists made hard work of one catch they took, as Narsingh Deonarine just held on to a chance after a mix-up with Hinds.
Bollinger took two wickets in his first two overs, including Gayle to a leading edge, and Ponting gave legspinner Steven Smith his full quota of overs on his one-day debut, which yielded an expensive 2-78.
Michael Clarke highlighted the gulf in fielding standards with a turn and direct hit which ran out Dwayne Smith.
Kieron Pollard took two wickets and made 45 for the West Indies, while tailenders Darren Sammy (47 not out) and Nikita Miller (22) showed some fight at the end.
Australia are chasing a first unbeaten season since 2000-01 and play the West Indies in two Twenty20 games, in Hobart on Sunday and at the SCG on Tuesday.
