Australia have survived a batting collapse to move 2-nil up in the women's Ashes defending 180 in a spin-dominated day in Naarm.
Ash Gardner had English captain Heather Knight's wicket for the second time this series and played a key role slowing England down while defending Australia's sub-par total.
The hosts lost 8-49 to be all out for 180 batting first but England failed to capitalise, rolled for 159.
Gardner, with spinning partner Alana King (4/25 off 10 overs) built the pressure slowing the middle overs before the visitors suffered a collapse of their own.
It came after a career-best performance with the ball from Alice Capsey, coupled by Sophie Ecclestone, saw English spin topple Australia's batting order.
Earlier in the day, Australia crashed out from a settled position at 2-131 nearing the midway point of the innings.
Fresh off a game-high 70 in Sunday's series opener, Australian skipper Alyssa Healy (29 from 19 balls) played main driver to the home side's positive start before Lauren Bell got England on the board at the start of the ninth over.
Opening partner Phoebe Litchfield (29) matched it before Ellyse Perry contributed with what would later prove a match-saving 64.
Gardner survived a near stumping sent on her second ball before departing bowled through the gate by Capsey for 2.
She had averaged 46 across her previous four ODI innings heading into the match.
Beth Mooney (12), Annabel Sutherland (11) and King (13) were the only other Australians to reach double figures.
In England's response, Kim Garth removed openers Maia Bouchier - caught by Gardner at point in the sixth over, Tammy Beaumont earlier on before the first change of bowler.
Knight was next to depart (Endland 3-68) caught-and-bowled during Gardner's third over.
Amy Jones gave a glimpse while remaining bats Danielle Wyatt-Hodge, Sciver-Brunt and Capsey fell by the 120 mark with the middle overs soaked up.
With pressure mounting, Gardner gave Capsey a let off with England five-down when she couldn't hold on to a chance before Garth made amends with the ball soon after.
Wickets tumbled and the required run rate blew out beyond England's reach.
Gardner ended with 1/23 off her ten overs, Australia collecting a 21-run win before the final ODI in Hobart on Friday.