Starting at 12 noon
Donna VEKIC (CRO) v [Q] Heather WATSON (GBR)
[Q] Monica NICULESCU (ROU) v Elise MERTENS (BEL) 
Aryna SABALENKA (BLR) v Lesia TSURENKO (UKR) 
Not before 7pm
Mihaela BUZARNESCU (ROU) v Alison RISKE (USA)
Raluca OLARU (ROU) / Olga SAVCHUK (UKR)  v Veronika KUDERMETOVA (RUS) / Aryna SABALENKA (BLR)
The quarterfinal between Elise Mertens and Monica Niculescu is a rematch of last year's Hobart International final, which Mertens won 6-3, 6-1 - though the roles have been reversed, as the Romanian was the No.3 seed in 2017 but a qualifier this year, while the Belgian was a qualifier last year and this week's No.2 seed.
In the pair's only other meeting, Mertens again beat Niculescu for the loss of just four games, 6-2, 6-2 in the first round of Biel/Bienne in April.
Donna Vekic and 2015 Hobart champion Heather Watson have split meetings - the Croat triumphed 6-3, 4-6, 7-5 on the green clay of Charleston in 2015, but the Brit gained revenge in Fed Cup round robin play last year 6-2, 6-4.
29-year-old Mihaela Buzarnescu has played five WTA main draws in her career, having debuted at this level at the US Open last year. This week marks her second quarterfinal-or-better showing following her Linz semifinal last October.
Aryna Sabalenka is one of three players to have started 2018 with back-to-back quarterfinal showings, having made the last eight in Shenzhen last week as well. The others are Barbora Strycova and Agnieszka Radwanska, both Auckland quarterfinalists who are still alive in Sydney.
Mihaela Buzarnescu is the only player remaining in the field who has not reached a WTA final; of the rest, Aryna Sabalenka is the only one who has never won a WTA title. The most decorated players left are Monica Niculescu, Lesia Tsurenko and Heather Watson, who have lifted three trophies apiece.