England Women fell behind in their quest to regain the Ashes following a 27-run defeat in the first NatWest one-day international at Lord's.
A late collapse saw Charlotte Edwards' side bowled out for 176 in 47.3 overs in reply to Australia's 203-8.
Edwards' 61 at the top of the order was the lone hand as the hosts lost 7-34 following the skipper's departure.
Defeat means England fell 4-2 points behind in an innovative series decided by results in Test, 50-over and Twenty20 matches.
After last week's only Test at Wormsley ended in a draw - meaning two points were shared - Australia snuck ahead in the series at Lord's thanks to their slow bowlers.
Spin duo Jess Jonassen (4-38) and Erin Osborne (3-39) did the majority of the damage to an England order that did not help themselves with a pair of run outs.
Katherine Brunt had earlier taken 3-29 to restrict Australia after opener Meg Lanning hit 56 from 64 balls.
The series continues at Hove on Friday with the second of three ODIs. Three more Twenty20s will follow, meaning there are 10 points still up for grabs.