No.4 seed Elina Svitolina faces 15-year-old prodigy Marta Kostyuk in an all-Ukrainian third round - the latest Slam round in which two Ukrainians have squared off. Indeed, it will be just the third all-Ukrainian Slam match ever, following Tatiana Perebiynis's defeat of Mariya Koryttseva in the first round of the 2008 US Open, and Lesia Tsurenko beating Kateryna Kozlova in the first round of Roland Garros last year.
Another regional milestone will be the third-round encounter between No.7 seed Jelena Ostapenko and No.32 seed Anett Kontaveit, a Latvian-Estonian encounter that will be the first all-Baltic battle in a major. The pair are familiar with each other, having teamed up back in 2013 to win the doubles title at the $25,000 event in Tallinn. In singles play, Kontaveit has had the advantage so far, having beaten Ostapenko in straight sets in both their sole junior match in 2011, and four years later on the grass courts of the Ilkley $50,000 ITF event.
No.2 seed Caroline Wozniacki had to save two match points against Jana Fett in the second round, winning 3-6, 6-2, 7-5. Eleven women have saved match point en route to winning a major in the Open Era, six of whom performed the feat at the Australian Open: Monica Seles in 1991 (faced one match point against Mary Joe Fernandez in the semifinals); Jennifer Capriati in 2002 (saved four match points against Martina Hingis in the final); Serena Williams in both 2003 (saved two match points against Kim Clijsters in the semifinals) and 2005 (saved three match points against Maria Sharapova in the same round); Li Na in 2014 (saved one match point against Lucie Safarova in the third round); and Angelique Kerber in 2016 (saved one match point against Misaki Doi in the first round).
Qualifier Luksika Kumkhum is the first Thai player in the third round of a Slam since Tamarine Tanasugarn made the Wimbledon quarterfinals in 2008, and the first Thai player in the third round of the Australian Open since Tanasugarn in 2003.
Marta Kostyuk has been hitting age-related milestones in every round this week. At 15 years and 6 months old, she is the youngest player to qualify for a Slam since Sesil Karatantcheva at the 2005 Australian Open (15 years and 5 months); the youngest player to win a round at a Slam since Catherine Bellis at the 2014 US Open (15 years and 4 months); the youngest player to make the third round of a Slam since Mirjana Lucic-Baroni at the 1997 US Open (15 years and 6 months); and the youngest player in the third round of the Australian Open since Martina Hingis in 1996 (15 years and 3 months). Should she beat Elina Svitolina to make the fourth round, Kostyuk would be the youngest player in the second week of a major since Anna Kournikova at the 1996 US Open (15 years and 2 months).
With her late-night defeat of Daria Gavrilova, Elise Mertens extended her main draw winning streak on Australian soil to 12. The Belgian has yet to lose in a Slam main draw to a player who has not been ranked in the Top 10 at some point: her four previous defeats came to Garbiñe Muguruza, Venus Williams twice and Madison Keys.
Two-time quarterfinalist Carla Suárez Navarro will take on Kaia Kanepi for the eighth time today in a rivalry stretching back to 2009. The Estonian won their only previous meeting on Australian hard courts, winning their Brisbane 2013 second-round match 6-2, 6-2, and leads the overall series 4-3 - including their most recent encounter in the third round of the 2014 US Open.
29-year-old No.19 seed Magdalena Rybarikova and 26-year-old Petra Martic are finding that experience is helping them put in the most consistent big-stage results of their career. Rybarikova has reached at least the third round at three consecutive Slams for the first time in her career, while Martic has made at least the third round at three of the past four majors - having reached this stage only twice in her previous 21 Slam main draws.
Kateryna Bondarenko is in the third round of the Australian Open for the second time since her return to the game from pregnancy in 2014. If she beats Magdalena Rybarikova, she would be the first mother in the second week in Melbourne since Casey Dellacqua in 2014 (and the first mother returning from giving birth since Kim Clijsters' semifinal run in 2012).
Alizé Cornet is bidding to make her first fourth round in Melbourne since 2009 - the first time the Frenchwoman made the second week of a Slam, and in which she held two match points over No.3 seed Dinara Safina before falling. Overall, she has gone 0-4 in Slam fourth rounds - the only active player with a worse record at that stage is Julia Goerges, whom Cornet beat in the second round this year, with 0-5.
All eyes will be on the Ukrainian clash as No.4 seed Elina Svitolina seeks to quash upstart Marta Kostyuk - but Peter Bodo has picked the 15-year-old to win at ESPN.com.
Joel Drucker's report on Angelique Kerber's defeat of Donna Vekic for Tennis.com is a paean to the dropshot.
Luksika Kumkhum's maiden run to the third round of a Slam is beginning to turn heads at home. The Thai qualifier has spoken to Lerpong Amsa-Ngiam for The Nation about her progress.
Hsieh Su-Wei's "box of tricks" proved too much for No.3 seed Garbiñe Muguruza on Thursday - and reporting for Reuters, Martyn Herman is appreciative.
ORDER OF PLAY
Find out when and where players are up on the fourth day in Melbourne.
From 2019, the WTA Finals will have a new home in Shenzhen. Watch WTA CEO and Samantha Stosur discuss the decision to move.