The world's No.1 junior and an unheralded wildcard are Australia's only remaining hopes of ending a 30-year junior girls title drought at Melbourne Park.
And only one of top seed Emerson Jones and wildcard Tahlia Kokkinis can make it to the final.
On Tuesday, Kokkinis joined 2024 finalist Jones in the tournament's third round by claiming a 6-2 3-6 6-4 win over unseeded Japanese player Kanon Sawashiro.
The two Australians are on the same side of the draw and will meet in the semi-finals if they both get that far.
Kokkinis next plays British qualifier Brooke Black while Jones plays Belarusian qualifier Yuliya Perapekhina.
Top seed Jones is attempting to become the first local girls' singles champion since Siobhan Drake-Brockman in 1995.
Jones will juggle her singles campaign with doubles.
She and Brit Hannah Klugman are the No.2 doubles seeds and fought back from a set down to beat Mia Pohankova and Jeline Vandromme in a third-set tiebreak.
In claiming the first-round match 2-6 6-4 10-8, Jones and Klugman teed up a second-round clash with Yuhan Wang and Kamonwan Yodpetch.
There are no local boys left in the draw after wildcard Ymerali Ibraimi lost to second seed Amir Omarkhanov 6-4 6-3, joining Cruz Hewitt and Duje Markovina in making a second-round exit.
