ORDER OF PLAY
MANOLO SANTANA -- 12:00 noon start
Following 1 ATP match, not before 2:30 p.m.
Belinda BENCIC (SUI) vs.  Simona HALEP (ROU)
Following 1 ATP match, not before 8:00 p.m.
 Sloane STEPHENS (USA) vs.  Kiki BERTENS (NED)
ARANTXA SANCHEZ -- 12:30 p.m. start
 Gabriela DABROWSKI (CAN) / XU Yifan (CHN) vs. [WC] Jelena OSTAPENKO (LAT) / Vera ZVONAREVA (RUS)
 HSIEH Su-Wei (TPE) / Barbora STRYCOVA (CZE) vs. Veronika KUDERMETOVA (RUS) / Galina VOSKOBOEVA (KAZ)
Belinda Bencic leads her head-to-head with Simona Halep by 2-1. Halep won their first meeting in the third round of Wimbledon in 2014, and Bencic leveled their rivalry in the 2015 Toronto final after Halep retired while trailing 3-0 in the final set.
Bencic won their most recent match in this year's Dubai quarterfinals; Bencic went on to win that event for her first title since the aforementioned 2015 Toronto championship.
Halep is up to a win-loss record of 24-6 in Madrid following her quarterfinal win over Ashleigh Barty on Thursday. The former World No.1 hoisted the Mutua Madrid Open trophy in 2016 and 2017. Halep can regain World No.1 by winning the title, following Naomi Osaka's quarterfinal loss to Bencic.
2017 US Open champion Sloane Stephens is into the semifinals of a WTA event for the first time this season, and has surpassed her previous best Madrid results, which were round-of-16 showings in 2014 and 2018.
Stephens brings a 2-0 head-to-head lead into her semifinal meeting with Kiki Bertens. Stephens beat Bertens on clay in three sets in Rome in 2013, and also won their round-robin match at last year's WTA Finals in Singapore.