Leg-spinner Poonam Yadav bowled India to an upset 17-run win over defending champions Australia in the opening game of the women's Twenty20 World Cup in Sydney today (21).

India were restricted to 132 for four off their 20 overs before a half-century from Australian opener Alyssa Healy appeared to have the home team on track for victory.

But then Yadav was brought into the attack.

Voted India's top female player last year, she bagged the crucial wickets of Healy, Rachael Haynes and Ellyse Perry, and was desperately unlucky not to grab a hat-trick in her match-winning 4-19.

“It is a great relief to win, I'm really happy for my girls,” said Indian skipper Harmanpreet Kaur.

“We knew this track is something where we could do well. If we could get to 140, we thought the bowlers can do the job. A bowler like Poonam is someone who leads from the front,” she added.

It was a big win for India, with only the top two from each of the two five-team groups making the knockout phase. A dangerous New Zealand, along with Sri Lanka and Bangladesh, are also in their group.

“They started off well and put us under the pump. At the halfway mark, 133 to chase, we thought we were in a pretty good place to win,” said Australian captain Meg Lanning.

“Unfortunately we didn't quite execute with the bat today. There was a lack of partnerships through the middle and India bowled extremely well. We came into this match as ready as we could have been but India outplayed us a little bit.” Lanning's team, four-time World Cup winners, were rarely tested through the second half of 2019 when they whitewashed an injury-ravaged West Indies and a developing Sri Lanka team in the short format.

But they slumped to defeat against major rivals India and England this month, before rallying to win their warm-up tri-series.

Australia won the toss at a near-full Sydney Showgrounds and elected to bowl.

It looked a dubious decision as exciting 16-year-old opener Shafali Verma powered India to 40 without loss after four overs. But the wheels came off with three quick wickets falling as the momentum shifted.

Verma made batting look easy as she plundered four fours off the world's top T20 bowler Megan Schutt in a single over.

But Jess Jonassen then pounced, nabbing Smriti Mandhana lbw for 10 before Perry tempted Verma into another big hit and she was caught at midwicket for 29.

Kaur lasted just five balls before being stumped as India lost three wickets for six runs.

Jemimah Rodrigues and the experienced Deepti Sharma steadied the ship with a 53-run stand but they could only reach 132.

Australia made a steady start, putting on 30 runs in the opening five overs before fast bowler Shikha Pandey removed Beth Mooney.

Healy kept the pressure on with a flurry of boundaries.

She brought up her 10th half-century with a six off Yadav, who promptly got her out next ball.

Yadav then tempted Haynes down the pitch and she was stumped before Perry was bowled for a golden duck.

Yadav was on a hat-trick and Jess Jonassen got an edge only for wicketkeeper Tanya Bhatia to fluff the catch, depriving her of glory.

But she soon struck again to snare Jonassen and Australia could find no way back.

India

S. Verma c Sutherland b Perry 29

S. Mandhana lbw b Jonassen 10

JI. Rodrigues lbw b Kimmince 26

H. Kaur st †Healy b Jonassen 2

DB. Sharma not out 49

V. Krishnamurthy not out 9

Extras: 7

TOTAL: 132/4 (20 Overs)

Fall: 1-41, 2-43, 3-47, 4-100

Australia

AJ. Healy c & b Poonam Yadav 51

BL. Mooney c Gayakwad b Pandey 6

MM. Lanning c †Bhatia b Gayakwad 5

RL. Haynes st †Bhatia b Poonam Yadav 6

A. Gardner c & b Pandey 34

EA. Perry b Poonam Yadav 0

JL. Jonassen c †Bhatia b Poonam Yadav 2

A. Sutherland st †Bhatia b Pandey 2

DM. Kimmince run out(Rodrigues/Sharma)4

M. Strano run out (Rodrigues/Pandey) 2

M. Schutt not out 1

Extras: 2

TOTAL:115 (19.5 Overs)

Fall: 1-32, 2-55, 3-67, 4-76, 5-76, 6-82, 7-101, 8-108, 9-113, 10-115