The side which was chasing 141 runs fell to 132 for the loss of 4 wickets had previously lost their only game in the competition to India on Tuesday, could not get to the target.
Forty from Deondra Dottin and 36 not out from Stacey Ann King got the side to within striking distance after Stefanie Taylor was run out for 24 and Kycia Knight was bowled for two.
Merissa Aguilleira made six before she departed as well as the side will now return to the Caribbean trophy less.
A wicket each for Rene Farrell, Sarah Coyte and Erin Osborne represented the wickets to fall.
Earlier, 35 from Elyse Villani, 29 from Meg Lanning and 30 not out from Alex Healy took the Aussies to 140 for the loss of 5 wickets.
The Aussies will await the winner of the second semi final which will tomorrow feature Pakistan and Sri Lanka.