The much-vaunted West Indian batting line-up came to the party to blow away the Australian attack and set-up a title clash against Sri Lanka courtesy a mammoth 74-run win at the Premadasa stadium in Colombo on Friday night.
Chris Gayle was at his devastating best, scoring an unbeaten 75 off 41 balls, and a brilliant cameo by Kieron Pollard towards the end helped West Indies scored 205 for 4, the highest score of 2012 World Twenty20.
The Australian innings folded up at 131 in the 17th over.
Chasing 206 to win would have been difficult on most grounds, but the slow pitch at Premadasa made the task trickier for the Aussies. Their cause wasn’t helped as opener David Warner was dismissed in the first over.
From then, Australia kept losing wickets at steady intervals as the West Indian spinners dominated proceedings.
Skipper George Bailey played a lone hand for the Aussies, making 63 off 29 balls with four sixes and six boundaries after adding 68 for the seventh wicket with Pat Cummins.
Darren Sammy's men take on hosts Sri Lanka in Sunday's final with both sides looking for their first World Twenty20 title.
The biggest Twenty20 win for the West Indies, surpassing their 70-run victory over Ireland in 2010, was celebrated by the entire team performing an energetic version of global hit "Gangnam Style" in the middle.
Leg-break bowler Samuel Badree removed both openers Warner and the dangerous Shane Watson to end with figues of 2 for 27. Ravi Rampaul took 3 for 16 and Pollard chipped with the ball as well taking 2 wickets for six runs from his sole over.
Earlier, Gayle smashed an unbeaten 75 off 41 balls to steer the West Indies to an imposing 205-4 in the World Twenty20 semi-final against Australia in Colombo on Friday.
The swashbuckling left-hander pounded six sixes and five fours after the West Indies elected to bat on what was considered a slow pitch unsuited to aggressive batting at the Premadasa stadium.
All-rounder Dwayne Bravo (37) helped Gayle add 83 for the third wicket from just 51 deliveries as the Australians wilted under lights.
Kieron Pollard hit 38 off 15 balls as the West Indies plundered 55 runs in the final three overs, including 25 off the last six deliveries by left-arm spinner Xavier Doherty.
Gayle, who lost his opening partner Johnson Charles in the third over, plodded for nine balls to make four before swinging Shane Watson for a six over long-off.
That opened the floodgates for an onslaught as Marlon Samuels and Gayle smashed Doherty for a six each in one over and Brad Hogg was greeted into the attack with another six from Samuels.
Samuels contributed 26 in a second-wicket stand of 41 with Gayle when he was bowled by fast bowler Pat Cummins attempting another big hit.
Gayle, who faced just 18 balls in the first 10 overs, still managed to bring up his half-century off 29 deliveries with the help of four sixes and three boundaries.
Both teams had met in a preliminary league match which was washed out after Australia reached 100-1 in 9.1 overs in pursuit of the West Indies' total of 191-8.
The Aussies were declared winners by 17 runs through the Duckworth-Lewis method.