Marketa Vondrousova's first-round defeat of No.6 seed Lara Arruabarrena was the 19-year-old's first WTA main draw win since a right thigh injury forced her to retire in the third set against Elina Svitolina in Stuttgart in May. The Czech will bid to make her first WTA quarterfinal since her title run in Biel/Bienne last April today against Elitsa Kostova.
No.7 seed Stefanie Voegele will play Tamara Korpatsch for the third time this year today. Their first career meeting was in the Lugano quarterfinals in April, with Voegele winning 6-4, 6-3; a month later in the first round of the ITF $100,000 event in Trnava, the Swiss player dropped a set, but still came back to win 4-6, 6-4, 6-1.
Wimbledon girls' runner-up Leonie Kung makes her WTA debut today against No.2 seed Johanna Larsson. The 17-year-old has two ITF $15,000 titles to her name - in Oslo last November and Martinique in January - and has reached two semifinals at ITF $25,000 level, in Montreux last year and Klosters last month. The youngest player in the Gstaad draw, Kung is currently ranked World No.413.
Mandy Minella's comeback from maternity leave returns to WTA level for the first time since Roland Garros today. The Luxembourger, who gave birth to daughter Emma last October, has picked up three ITF $25,000 titles since resuming her career in February, including two in her last four tournaments, and compiled a 31-13 record overall. However, Minella is 0-3 in WTA main draws as a mother so far. She is 2-0 against her first-round opponent, Tereza Martincova, having defeated the Czech in the qualifying rounds of Hobart and Indian Wells in 2017.
Mona Barthel is bidding to reach her fourth WTA quarterfinal of the year today (following Budapest, where she reached the last four, Lugano and Nottingham). The German is 2-0 against Evgeniya Rodina, who is fresh off a career-best fourth-round Slam showing at Wimbledon, and who is seeking to reach her first WTA quarterfinal since Guangzhou last year.
ORDER OF PLAY
ROY EMERSON ARENA (starts 10.30am)
Mandy MINELLA (LUX) vs Tereza MARTINCOVA (CZE)
Marketa VONDROUSOVA (CZE) vs Elitsa KOSTOVA (BUL)
Xenia KNOLL (SUI) / Veronika KUDERMETOVA (RUS)  vs Viktorija GOLUBIC (SUI) / Jil TEICHMANN (SUI)
Not before 3.30pm
[WC] Leonie KUNG (SUI) vs Johanna LARSSON (SWE) 
Not before 5.30pm
Stefanie VOEGELE (SUI)  vs Tamara KORPATSCH (GER)
COURT 1 (starts 10.30am)
Sara SORRIBES TORMO (ESP) vs [Q] Valentyna IVAKHNENKO (RUS)
Mona BARTHEL (GER) vs Evgeniya RODINA (RUS)
Alexa GUARACHI (CHI) / Desirae KRAWCZYK (USA) vs [Alt] Tamara KORPATSCH (GER) / Diana MARCINKEVICA (LAT)