No.3 seed Sofia Kenin and Lauren Davis have met once before, in the first round of the 2017 US Open - with Kenin triumphing 7-5, 7-5 to notch up her first Grand Slam main draw victory. Davis, who was runner-up here in 2016 to Yanina Wickmayer, is the only player remaining in the field who has previously reached the Washington final after Sloane Stephens and Anastasia Pavlyuchenkova both suffered first-round losses.
Four teenagers are still alive in the draw: 17-year-olds Hailey Baptiste and Catherine McNally and 18-year-olds Iga Swiatek and Varvara Gracheva. Baptiste, who upset No.2 seed Madison Keys on her WTA debut yesterday, faces Kristina Mladenovic for the first time today; while Lugano runner-up Swiatek will bid to make her second career WTA quarterfinal against 2016 semifinalist Jessica Pegula.
Former junior World No.3 Anna Kalinskaya snapped a 12-match losing streak in WTA main draws stretching back to Gstaad 2017 with her first-round defeat of Nao Hibino. The Russian has come through qualifying at this level 10 times, including at four Grand Slams, and will bid for her second career Top 50 win over No.8 seed Monica Puig - having previously upset Caroline Garcia in the first round of Kuala Lumpur in 2017.
ORDER OF PLAY
STADIUM (starts 2pm)
After 3 ATP matches, not before 9pm
Kristina MLADENOVIC (FRA) vs [WC] Hailey BAPTISTE (USA)
GRANDSTAND (starts 1pm)
Jessica PEGULA (USA) vs Iga SWIATEK (POL)
Lauren DAVIS (USA) vs  Sofia KENIN (USA)
 Monica PUIG (PUR) vs [Q] Anna KALINSKAYA (RUS)
HSIEH Yu-Chieh (TPE) / YOU Xiaodi (CHN) vs [WC] Coco GAUFF (USA) / Catherine MCNALLY (USA)
COURT 4 (starts 1pm)
After 3 ATP matches
Alison BAI (AUS) / Elixane LECHEMIA (FRA) vs  WANG Yafan (CHN) / YANG Zhaoxuan (CHN)
COURT 5 (starts 1pm)
After 1 ATP match
Naomi BROADY (GBR) / Sharon FICHMAN (CAN) vs Beatrice GUMULYA (INA) / Jessy ROMPIES (INA)
Quinn GLEASON (USA) / Ingrid NEEL (USA) vs  Maria SANCHEZ (USA) / Fanny STOLLAR (HUN)