The legspinner bamboozled England with 4-45 - her best Test figures - as Australia grabbed complete control of the match in their quest for an unprecedented multi-format whitewash.
Australia will bat for up to 24 overs before stumps on Thursday as they seek to cut England's lead in the day-night Test.
Teammates congratulate Alana King (second right) on one of her four wickets against England. (James Ross/AAP PHOTOS)
Bowling with the Shane Warne Stand behind her, King bowled 23 overs unchanged to destroy England's middle order, even taking the prized scalp of Nat Sciver-Brunt (51).
She claimed three of the four wickets of the second session, as England went to the dinner break at 7-142.
England only added another 28 runs before their innings ended 50 minutes into the final session following a clumsy run-out.
Pink-ball Tests have traditionally been the domain of fast bowlers in men's cricket, but King proved spin has a vital place, too.
But Australia are sweating on the fitness of superstar Ellyse Perry, who landed awkwardly on her hip while diving in the field.
The 34-year-old didn't return to the field after going off to be assessed during the second session.
England's Natalie Sciver-Brunt showed plenty of resistance with a half-century. (James Ross/AAP PHOTOS)
Earlier, Kim Garth skittled England's top order by striking in the first over, dismissing Maia Bouchier (2) thanks to a stunning catch by wicketkeeper Beth Mooney.
The Irish-born star later claimed the crucial wicket of England captain Heather Knight (25), who looked set to deliver on her promise of playing her best when she has a point to prove.
Knight was trapped lbw, not even bothering to use a review as she walked off to leave Sciver-Brunt to bat with Sophia Dunkley.
Quick Darcie Brown (2-47) took the other wicket of the first session, removing opener Tammy Beaumont (8).
England are trying to avoid an embarrassing 16-0 whitewash after losing the three ODIs and three Twenty20s.
Debutant Georgia Voll, who took a courageous catch, was presented with her baggy green by Australia legend Belinda Clark.
Introducing Australian Women's Test cap #185, Georgia Voll! 🙌— Australian Women's Cricket Team � (@AusWomenCricket) #Ashes pic.twitter.com/EIDc8BX4rsJanuary 30, 2025
The 21-year-old will open the batting with fellow young gun Phoebe Litchfield, with captain Alyssa Healy shifting to No.4.
Under a cloud after missing the T20s with a foot injury, Healy was trusted by selectors to make it through the first women's Test at the MCG since 1949.
She won the toss, electing to send England in to bat on a green-looking pitch.
Alyssa Healy an hour out from the toss... — cricket.com.au (@cricketcomau) #Ashes pic.twitter.com/oFPhWVuFFIJanuary 30, 2025
Healy isn't taking the gloves in this match, with Mooney to continue wicketkeeping after handling it well during the T20s.
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