Eighteen-year-old Sophie Ecclestone marked her Test debut with two wickets, but a patient half-century from Ellyse Perry helped Australia women close in on England's first-innings total on day two at the North Sydney Oval.
Left-arm spinner Ecclestone removed Beth Mooney and Alex Blackwell to reduce the hosts to 61 for three in the inaugural day-night Ashes Test, but a 73-run stand between Perry, who made an unbeaten 70, and captain Rachel Haynes (33), helped them reach the close on 177 for five.
That left them 103 runs behind England, who were earlier dismissed for 280 after resuming on 235 for seven.
Australia lead the multi-format points-based series 4-2 and will retain the Ashes if they win in Sydney.
A strong start from the home side was ended by Laura Marsh, who had Nicole Bolton caught by Anya Shrubsole for 24.
Ecclestone then took centre stage, claiming her first victim with plenty of good fortune when Mooney (27) went after a short ball but succeeded only in thumping it straight to Nat Sciver at midwicket.
Her second arrived seven runs later and was all her own work, deceiving Blackwell (six) with a drifting delivery to trap her lbw.
A brilliant catch from Sarah Taylor removed Elyse Villani, the wicketkeeper showing remarkable reactions to hold an edge standing up to a Shrubsole delivery.
But Perry and Haynes then combined to take the match to England, pushing the pace under the lights as they took the score from 95 for four to 168 for five.
A fired-up Katherine Brunt brought the partnership to an end when, the very next ball after having Haynes escape when she edged between first and second slip, she trapped the Australian captain lbw.
The impressive Perry was still there at the end, though, ending the day on 70 from 173 balls, including 10 fours, to give the tourists plenty of food for thought heading into day three.
At the start of the day England's bid to reach 300 fell short as they added 45 to their overnight total, Shrubsole the biggest contributor of the morning with 20.