VOLVO CAR STADIUM -- 10:45 a.m. start
[WC] Chloe BECK (USA) / Emma NAVARRO (USA) vs.  Lucie HRADECKA (CZE) / Andreja KLEPAC (SLO)
Not before 1:00 p.m.
 Belinda BENCIC (SUI) vs.  Petra MARTIC (CRO)
 Caroline WOZNIACKI (DEN) vs.  Maria SAKKARI (GRE)
 Sloane STEPHENS (USA) vs.  Madison KEYS (USA)
Not before 7:00 p.m.
Monica PUIG (PUR) vs.  Danielle COLLINS (USA)
Irina KHROMACHEVA (RUS) / Veronika KUDERMETOVA (RUS) vs.  Raquel ATAWO (USA) / Katarina SREBOTNIK (SLO)
2016 Volvo Car Open champion Sloane Stephens takes a 3-0 head-to-head lead into her match with 2015 Charleston finalist Madison Keys. They have played each other in two of the biggest Grand Slam matches over the last two years: the 2017 US Open final and the semifinals of the 2018 French Open.
Monica Puig and Danielle Collins have split their two previous encounters. Collins won their most recent match, in the round of 16 at last year's Miami Open.
This is the first meeting between Belinda Bencic and Petra Martic. Bencic made the semifinals of the Volvo Car Open in her debut appearance in 2014, as a 17-year-old qualifier ranked World No.140.
Maria Sakkari defeated Caroline Wozniacki in their only previous meeting, in the second round in Wuhan in 2017. That was the first Top 10 win of Sakkari's career.