Ashleigh Barty will be looking to make it Australia's day as the opening grand slam of the year moves into the fourth round.
The Young Australian of the Year has the chance to make it back-to-back quarter-final appearances at her home grand slam, potentially a replay of last year's last eight match against Petra Kvitova.
But first she has to get past Alison Riske on Sunday.
The American beat Barty in their only previous encounter in a fourth-round clash in Wimbledon last July.
Riske's heavy hitting with present another issue for Barty to work through but the French Open champion has been pleased with how her mental game has been working during the Australian summer.
"I've been able to find a way and problem solve through a lot of my matches across the last two or three weeks," she said.
For her part, Kvitova will need to get over the top of improved Greek Maria Sakkari.
It may be Australia Day but the international contingent is strong with 13 nationalities represented in the eight singles matches being played on Sunday.
The youngest woman in the tournament will feature in 15 year-old Coco Gauff while 38 year-old Roger Federer also takes to the court.
Gauff's coming age arrived on Friday when the teen defeated defending champion Naomi Osaka and she'll be looking to back that up with a win over 14th seed and compatriot Sofia Kenin to lock in her first grand slam quarter-final.
Federer will be backing up after his epic clash with Australian John Millman with the 20-time grand slam looking for an easier time against unseeded Hungarian Marton Fucsovics.
His conqueror in the 2019 Wimbledon final, Novak Djokovic, will face plucky Argentine Diego Schwartzman.
It's expected to rain aces in the first match up on Margaret Court Arena when Canada's Milos Raonic plays Croatia's 2018 finalist Marin Cilic.
The winner of that clash will likely play Djokovic in a quarter-final.
In other fourth round matches China's Wang Qiang takes on Tunisian surprise packet Ons Jabeur and Italian Fabio Fognini is up against American Tennys Sandgren.
Australian Associated Press