Rachael Haynes and captain Meg Lanning put on 95 as the defending champions flirt with a second straight defeat before eventually prevailing
Hosts Australia finally got their T20 World Cup defence off the ground with a five-wicket victory over Sri Lanka - but not before being given an almighty scare in Perth.
Sri Lanka had looked on course to set a competitive target after a half-century from Chamari Atapattu but from 101 for 3 with 22 balls left, they ended on 122 for 6.
Nicola Carey and Molly Strano finished with two wickets apiece on a surface where taking pace off the ball appeared to be key.
Set just 123 for victory, the four-time world champions were in deep trouble from the outset with Udeshika Prabodhani and Shashikala Siriwardene combining to reduce Australia to 10 for 3.
But Rachael Haynes and captain Meg Lanning settled the pursuit down with a partnership of 95 for the fourth wicket.
After curbing the Sri Lanka threat - left-armer Prabodhani bowled her full allocation early and field settings became increasingly defensive - Australia went on the attack themselves.
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Despite the imperiousness of Haynes and Lanning, Sri Lanka will still be wondering how they didn't inflict a second group defeat on Australia, who had lost to India in their opening game.
Haynes was dropped at mid-on on 26 and then on the boundary having reached 60 before she was eventually dismissed without scoring further. But by then Australia were on the brink of victory.
Meanwhile, Lanning should have been given out on six when she feathered through to the 'keeper, but the umpires were unmoved.
Atapattu had earlier burned Sri Lanka's only review and her inability to object to the decision was key to the final outcome, as Australia cruised to victory with three balls remaining.
Lanning remained unbeaten on 41 from 44 balls and struck the winning runs to spark contrasting scenes on the outfield, with Sri Lanka dejected and Australia relieved after belatedly igniting their campaign.