“A bowler like Poonam is someone who leads from the front. We were expecting a great comeback from her. Our team is looking nice, earlier we depended on two-three players,” India skipper Harmanpreet Kaur said after the match.
Poonam, who missed the preceding tri-series due to a hand injury, also got good support from other bowlers including pacer Shikha Pandey.
The 28-year-old from Agra was on a hat-trick but narrowly missed out as wicket-keeper Taniya Bhatia dropped a difficult chance.
The tournament-opener saw a record 13,000 plus attendance with a sizeable chunk supporting India.
India next play against Bangladesh in Perth on February 24.
“It was great for me to come back from injury and perform like this. It was the third time that I was on a hat-trick but satisfied that I was able to do the job for the team,” said Poonam at the post-match presentation.
Australia were off to a good start to their chase with opener Alyssa Healy making a 35-ball 51, laced with six boundaries and a six.
However, Indian spinners led by Poonam triggered a collapse as Australia suddenly slipped to 82 for six.
Poonam (4/19) snapped four wickets, two in successive deliveries in the 12th over, to break the back of Australia’s chase.
Ashleigh Gardner (34 off 36) tried her bit but didn’t get any support from the other end.
Earlier, India squandered a flying start to end up with a below-par total.
Sixteen-year-old Shafali Verma took India to 40 for no loss in four overs with a typically aggressive 29 off 15 balls but her fall derailed the innings as the other batters disappointed.
Deepti Sharma made a composed 46-ball 49 in the second half of the innings but the firepower that India needed in the death overs was badly missing.
India were cruising initially with Shafali taking the opposition to the cleaners, hitting five fours and a six.
However, left-arm spinner Jess Jonassen (2/24) snapped two quick wickets, Smriti Mandhana (10 off 11) and Harmanpreet (2 off 5) to reduce India to 47 for three.
Deepti then shared 53 runs with Jemimah Rodrigues (26 off 33) to bring up the 100 in the 16th over.
For Australia, Ellyse Perry (1/15) and Delissa Kimmince (1/24) were the other wicket-takers.