Venus Williams leads the head-to-head against WTA World No.1 Simona Halep 3-2.
Halep, however, has the consolation of knowing that the No.1 seed for the Australian Open has never gone out in the third round during the Open era.
Venus' last win over a World No.1 came back in 2017, when she beat Angelique Kerber in Miami.
Naomi Osaka has a 20-2 winning record against players outside the Top 20 at Grand Slams.
Hsieh Su-Wei has made the semifinals or better in four of her last seven events.
No.6 seed Elina Svitolina has a 1-0 career head-to-head record against Zhang Shuai.
Karolina Pliskova has successfully won seven of her 11 third-round Grand Slam matches.
Elise Mertens has a 1-7 record against Top 20 opponents in majors. Her only win previously came against Svitolina in Australia last year.
Wang Qiang, who is Anastasija Sevastova's first Chinese opponent at a Slam, is chasing a Round of 16 berth for the first time.
Dayana Yastremska has a 1-0 record against former WTA World No.1s and is 2-0 against Grand Slam champions.
Serena has won 18 successive Australian Open sets, dating back to 2017. She has dropped only six games in the first two rounds.
Timea Bacsinszky is chasing her 35th career win over a Top 20 player when she faces Garbiñe Muguruza, who has lost only once in 12 visits to the third round of Grand Slam events.
ORDER OF PLAY
A selection of the best of wtatennis.com and the wider sports media.
Amanda Shalala of Vogue looks at the history of female tennis players who have changed the game for good.
Stefanie Graf believes that Serena has what it takes to break Margaret Court's record of Grand Slam titles.
Maria Sharapova's victory over Caroline Wozniacki will have been especially sweet for the Russian, says ESPN's Alyssa Roenigk.