Sri Lanka’s captain Chamari Athapaththu’s decision to bat first backfired as her side could only accumulate 93/7 in the allotted 20 overs.
The Asian champions had a disastrous start to their innings as they lost both their openers Vishmi Gunaratne and Athapaththu inside four overs with just six runs on the board.
Following the early debacle, Harshitha Samarawickrama offered some fight with her cautious 23-run knock before falling victim to Sophie Molineux, leaving Sri Lanka in tatters at 56/4 in 13 overs.
Nilakshika Silva then took the reigns of Sri Lanka’s batting expedition but remained devoid of any notable support from the other end.
She remained the top-scorer for Sri Lanka with a 40-ball 29.
Megan Schutt was the standout bowler for Australia, courtesy of her economical bowling figures of 3/12 in her four overs, followed by Molineux with two wickets, while Ashleigh Gardner and Georgia Wareham shared two wickets between them.
In response, Australia had an alike start as they lost three wickets, including their captain Alyssa Healy (4) and experienced all-rounder Ellyse Perry (3), inside the batting powerplay with just 35 runs on the board.
But the defending champions recovered, courtesy of an anchoring partnership between Mooney and Gardner.
The duo added 43 runs for the fourth wicket until Gardner perished with Australia in touching distance to a triumphant start to their Women’s T20 World Cup title defense.
Gardner made 17 off 15 balls with the help of three fours.
Mooney then joined forces with Phoebe Litchfield, nine off nine, to make sure there were no further hiccups in the modest run chase.
The opening batter top-scored for Australia with an unbeaten 43 off 38 deliveries, laced up with four fours.
For Sri Lanka, Sugandika Kumari, Inoka Ranaweera and Udeshika Prabodhani made one scalp each.