Chasing 289 for victory, West Indies got off to a poor start before Shai Hope (68) and Nicholas Pooran (40) laid the platform for the power-hitters, but the Starc-led Australian attack kept them on a tight leash, restricting them to 273-9.
After leg-spinner Adam Zampa removed Pooran, fast bowler Pat Cummins had Hope caught at mid-on in the 35th over to deliver a body blow to the Windies who never recovered.
Starc claimed Jason Holder (51), Carlos Brathwaite and Sheldon Cottrell in the final five overs to finish with 5-46 in his 10 overs.
Earlier, Nathan Coulter-Nile struck the highest World Cup score for a number eight batsman as his 92 took Australia to a competitive total after they lost their first five wickets for 79 runs.
Steve Smith (73) played the anchor role to perfection, combining with Coulter-Nile to stage a rescue act with a 102-run stand for the seventh wicket.
(Production: Kurt Hall)