Caroline Wozniacki has won the last three meetings with Magdalena Rybarikova, triumphing in Tokyo in 2013 and both Cincinnati and New York the following year. Slovakian Rybarikova had won the first encounter, in straight sets in Pattaya City in 2009.
Caroline Wozniack is attempting to reach the last eight in Melbourne for the third time - but first since 2012.
Magdalena Rybarikova has won as many main draw matches at this year's Australian Open as in her previous eight visits (three).
Elina Svitolina is seeking a first career victory over Denisa Allertova, having lost their only previous meeting in straight sets in Doha two years ago.
Elina Svitolina's previous best showing at the Australian Open was the third round - a stage she went out in in 2014, 2015 and 2017.
Denisa Allertova dropped just 12 games across her three qualifying rounds to reach the main draw. No other player dropped fewer. She is also one of two players in the bottom half of the main draw to have reached this stage without dropping a set.
Anett Kontaveit is competing in the last sixteen of a Grand Slam for the second time, having also reached the fourth round at the US Open in 2015 - where she lost to Venus Williams.
Carla Suarez Navarro hopes to emulate her Melbourne showing of 2009 and 2016, when she reached the last eight, in what remains her best Grand Slam performances.
Petra Martic, who turned 27 on Friday, is already enjoying her best Australian Open, her reaching the last sixteen besting her previous best (second round in 2011).
Making her main draw debut, Elise Mertens is the first Belgian to reach the last sixteen in Melbourne since Yanina Wickmayer, in 2015.
Nina Pantic of Tennis.com watched in awe as Simona Halep and Lauren Davis served up an epic on Saturday.
ESPN's Jerry Bembry saw plenty of positives in Davis' display, despite defeat to the top seed.
Jon Pierik of The Age praised the performance of home favorite Ashleigh Barty in defeat to Naomi Osaka.
ORDER OF PLAY
All the details of who plays when on the seventh day in Melbourne.
An exhausted Simona Halep reflects on her marathon match against Lauren Davis: