No.8 seed Ekaterina Alexandrova has scored two wins in two matches against Russian compatriot Anna Kalinskaya by almost identical scorelines - 7-5, 6-0 in the semifinals of the 2017 Shenzhen ITF 60K event and 7-6(4), 6-0 in St Petersburg qualifying this January. Alexandrova, who has won 23 of her past 27 indoor matches stretching back to her Linz final run last October, is just 1-7 against her countrywomen in WTA main draws, while Kalinskaya is 1-2, having scored her first win over a fellow Russian in the first round against Anastasia Potapova.
No.3 seed Belinda Bencic's only previous meeting with Polona Hercog was in Rome qualifying in 2014 when she was 17 years old - and which she won 6-7(5), 6-3, 6-4. Hercog has stretched a Top 10 player to three sets on four occasions this season - Simona Halep in Miami and Eastbourne, Sloane Stephens at Roland Garros and Kiki Bertens in Beijing - but is nonetheless just 1-28 against players in that echelon; a win for the Slovenian today would mark her first Top 10 scalp since defeating Marion Bartoli in the second round of Charleston 2012.
No.3 seed Donna Vekic will break the Top 20 for the first time with a win over Karolina Muchova in their first meeting today.
No.5 seed Dayana Yastremska is bidding for her second career quarterfinal at Premier level, having reached her first three weeks ago in Wuhan, while qualifier Kirsten Flipkens is seeking to make her first Premier quarterfinal since New Haven 2017.
ORDER OF PLAY (all courts start 11am)
Polona HERCOG (SLO) vs [3/WC] Belinda BENCIC (SUI)
[WC] Anna KALINSKAYA (RUS) vs  Ekaterina ALEXANDROVA (RUS)
After 3 ATP matches, not before 8pm
 Donna VEKIC (CRO) vs Karolina MUCHOVA (CZE)
After 2 ATP matches, not before 2pm
 Dayana YASTREMSKA (UKR) vs [Q] Kirsten FLIPKENS (BEL)
Natela DZALAMIDZE (RUS) / Lidziya MAROZAVA (BLR) vs  Gabriela DABROWSKI (CAN) / Katerina SINIAKOVA (CZE)
Shuko AOYAMA (JPN) / Ena SHIBAHARA (JPN) vs [WC] Alina CHARAEVA (RUS) / Sofya LANSERE (RUS)
After 1 ATP match
 Timea BABOS (HUN) / Kristina MLADENOVIC (FRA) vs Nadiia KICHENOK (UKR) / Raluca OLARU (ROU)
Veronika KUDERMETOVA (RUS) / Katarina SREBOTNIK (SLO) vs Ekaterina ALEXANDROVA (RUS) / Aliaksandra SASNOVICH (BLR)
 Kirsten FLIPKENS (BEL) / Bethanie MATTEK-SANDS (USA) vs Olga DANILOVIC (SRB) / Ajla TOMLJANOVIC (AUS)