West Indies beat Australia by 74 runs in the second semi-final on Friday to book a place in Sunday's final against hosts Sri Lanka.
Chris Gayle (75 not out) and Kieron Pollard (38) toyed with Australia's bowling as West Indies posted a mammoth 205 for four before returning to bowl out Australia for 131 in 16.4 overs.
Australia captain George Bailey top-scored for his team with a 29-ball 63.
Gayle blasted six sixes and five boundaries in his 41-ball knock and Pollard (38 off 15 balls) hit three successive sixes in the final over of the innings to take West Indies past the 200-run mark.
Dwayne Bravo (37) also feasted on Australia's bowling attack, hitting three sixes in his 31-ball knock, while Marlon Samuels chipped in with 26 runs.