A clash of former champions will take place between No.21 seed Angelique Kerber, the 2016 winner, and Maria Sharapova, who lifted the trophy in 2008. The pair's only previous meeting here was also in the third round, in 2012, when No.4 seed Sharapova beat No.30 seed Kerber 6-1, 6-2. The Russian leads their overall head-to-head 4-3, including 2-0 on outdoor hard courts - but has not beaten the German since 2013, with Kerber taking their two most recent encounters at Wimbledon 2014 and Stüttgart 2015.
No.6 seed Karolina Pliskova owns a 5-2 head-to-head lead over compatriot Lucie Safarova - but her only two losses to the No.29 seed have been on clay in Prague. Their most recent meeting was in the first round of Beijing in 2016, which Pliskova won 6-7(7), 6-1, 6-4.
No.18 seed Ashleigh Barty is looking to become the first Australian woman to make the second week in Melbourne since Casey Dellacqua in 2014. She faces Naomi Osaka, who is herself bidding to become the first Japanese woman to make the Australian Open fourth round since Ai Sugiyama's quarterfinal run in 2000. 20-year-old Osaka would be the youngest Japanese player to make the second week of a Slam since 19-year-old Sugiyama at Roland Garros in 1995.
Bernarda Pera is the eighth lucky loser to advance to the third round of a Slam since 1987, when all Grand Slams became 128-draws, and the first since Ons Jabeur at Roland Garros last year. The American is also the first lucky loser to make the third round of the Australian Open since Sandra Kleinova in 1997. Only four lucky losers have reached a Slam round of 16 in the Open Era; Pera is bidding to become the first since Argentina's María José Gaidano at the 1993 US Open.
Hsieh Su-Wei, the conqueror of Wimbledon champion Garbiñe Muguruza on Wednesday, first played Australian Open qualifying as a 15-year-old in 2002. She made her main draw debut here in 2008, beating Aravane Rezai to reach the fourth round before falling to Justine Henin - but today marks just her second time in a Slam third round since then.
Last year, Aliaksandra Sasnovich and Aryna Sabalenka were the underdogs who led the Belarusian Fed Cup team to a surprise final - which came down to the wire in Minsk as they fell 2-3 to the USA. Both have carried their form into 2018: Sabalenka began the year with back-to-back quarterfinals before taking No.18 seed Ashleigh Barty to three sets in Melbourne, while Brisbane finalist Sasnovich has put together a 9-1 record this year already - and is in her maiden Slam third round after falling in the second round on six previous occasions.
Naomi Osaka is seeking to break a 0-5 record in Slam third rounds today against No.18 seed Ashleigh Barty. That record currently ties the Japanese player with Christina McHale, Anastasia Rodionova and Carina Witthoeft among active players for the most appearances in a Slam third round without a second week showing. Osaka improved to an 8-14 career record against Top 20 players with her second-round defeat of Elena Vesnina.
Last year, Barbora Strycova reached the second week at a Slam in consecutive years for the first time in her career when she made her second Australian Open fourth round. Today, the No.20 seed is looking to make it three times in a row.
Ana Bogdan improved her career record against Top 20 players to 3-1 this week with her first-round defeat of No.11 seed Kristina Mladenovic, and has the chance to score another against No.17 seed Madison Keys today. Bogdan, who will crack the Top 100 for the first time after the Australian Open, is a former junior World No.2 whose best junior Slam showing came in Melbourne in 2009, when she beat Mladenovic en route to the semifinals before losing to eventual champion Ksenia Pervak.
No.1 seed Simona Halep faces Lauren Davis in her bid to make the second week at the Australian Open for the first time since 2015, and third time overall. Davis has a 3-8 career record against the Top 10, with her best win coming over World No.4 Victoria Azarenka, 6-0, 7-6(2) in the second round of Indian Wells in 2014.
23-year-old lucky loser Bernarda Pera had only played one WTA Tour-level match prior to the Australian Open - but her run to the third round means that it's time to get to know the American. Nina Pantic has put together a Pera primer at Baseline.
Ashleigh Barty has been rising to the occasion this week, surviving two hard-hitting opponents and thriving under home pressure. Michael Gleeson looks at how far she's come and how far she could go for the Sydney Morning Herald.
ORDER OF PLAY
Find out when and where players are up on the fourth day in Melbourne.
After slumping from World No.1 to No.21 over the course of 2017, the renaissance of Angelique Kerber has been one of the most welcome narratives of 2018 so far. Hear her tell the press how she turned her form around.