Imagine falling asleep after Australia's defeat in the T20 World Cup opener against India on Friday and then waking up no sooner than the third over of their 123-chase against Sri Lanka three days later, only to find the four-time winners and defending champions are staring at another potential league stage defeat.

Australia have never lost to Sri Lanka across limited-across formats; at 3 for 10 in 3.2 overs, it seemed like they were heading for a historic defeat at WACA. The swing of left-arm pacer Udeshika Prabodhani and turn from offspinner Shashikala Siriwardene had suddenly left the vulnerability of a seemingly impenetrable line-up exposed even further after Poonam Yadav spun them into a tangle in Sydney.

Against Yadav's wristpin, their batters didn't have any answers. On Monday, Prabodhani's inswingers felt like jumbled alphabets to this world-beating side. A 4.5-degree swing from the left-arm pacer's second ball of the innings would get the better of one of the world's bests. Alyssa Healy, coming off a blazing 51 in the T20 World Cup opener, was sent packing by a 98kph incoming delivery.

At 34, Prabodhani is one of Sri Lanka's most experienced players, their most economical bowler on Sri Lanka's tour of Australia across limited-overs formats, and senior-most among the rare few left-arm pacers on the women's international circuit. "She's the best bowler in Sri Lanka and she has a lot of experience," the captain Chamari Atapattu had said about Prabodhani at the pre-match press conference on Sunday. "We call her 'the silent killer'".

"I'm sure there was a couple of nerves today, but I hope we showed today the character that has been there in the group." Rachel Haynes

Prabodhani's first four balls in the second over denied No. 3 Ashleigh Gardner any runs. The fifth, a carbon-copy of the ball that dismissed Healy, hooped back down the line to crash into the top of middle and leg. With just eight on the scoreboard, the urgency among the Sri Lankans fielding inside the circle lent a degree of imminence to a third wicket that was only three balls away.

In the recent past, the left-hand opener Beth Mooney has been peerless at the top within the Australian set-up, playing starring roles in the title triumphs of her WBBL side Brisbane Heat and, more recently, Australia in the tri-series. Her last two 20-over outings, though, were worth a combined 16 runs. At the WACA, she would add only another six runs, her seven-ball stay cut short with a flighted away-going delivery from Siriwardene.

For the second time in four nights, the focus of an Australia chase fell squarely on the side's highly-regarded batting depth. The chastening defeat against India had left questions to be asked of this purported strength, but unlike Friday night where the entire line-up seemed wanting in resilience after Healy's dismissal, resistance against Sri Lanka came in the form of a 95-run stand between the Australia captain Meg Lanning and her deputy Rachael Haynes.

"I thought today we showed a little bit of our character," Haynes said after her 47-ball 60. "World Cup tournaments aren't easy. Playing at home, you're really enjoying the opportunity to do it but you kind of escape from the fact that it's different from a normal series where perhaps you can drop a game here and there and get back in the contest whereas World Cup cricket you have to keep winning. That's the nature of the beast.

"I'm sure there was a couple of nerves today, but I hope we showed today the character that has been there in the group. To be able to get over the line right at the end there will hopefully correct some of the momentum heading into the rest of the tournament."

At least four dropped chances when the pair were batting and a botched use of DRS left Sri Lanka no room to review a Lanning caught-behind.

"It didn't feel easy to bat out there, to be honest," Haynes said. "I felt like I cloffed nearly every shot that I played today, perhaps with the exception of one. We knew, more than anything, that the partnership was really valuable. So it was nice to be able to come together and get us back in a position where we could attack.

"I think we talk a lot about having match-winning contributions, and sometimes it requires beginnings, and sometimes it requires impactful innings in T20 cricket. Today I think Meg and I came together and we did that job. We won the game of cricket for our team. It was obviously an important moment because we needed to win today to stay in the contest.

"But, yeah, from my point of view, it was just really nice to share in that with Meg. Today is also her 100th match. So it was really nice to not only win but obviously win a big game for her too."