Starting at 1pm
Alizé CORNET (FRA) v Marta KOSTYUK (UKR)
Not before 3pm
Carina WITTHOEFT (GER) v Marketa VONDROUSOVA (CZE)
Not before 8.30pm
Daria KASATKINA (RUS) v Magdalena RYBARIKOVA (SVK)
Starting at 11.30am
Veronika KUDERMETOVA (RUS) v Varvara LEPCHENKO (USA)
Not before 1.30pm
Zarina DIYAS (KAZ) v Kaia KANEPI (EST)
Not before 4.30pm
Nicole MELICHAR (USA) / Kveta PESCHKE (CZE) v Alla KUDRYAVTSEVA (RUS) / Andrea SESTINI HLAVACKOVA (CZE) 
Laura Siegemund is the defending champion, having beaten Kristina Mladenovic in the 2017 final.
Kasatkina and Rybarikova have never played each other before.
Kasatkina competed in the 2017 tournament, losing in the Round of 32 to Elena Vesnina 7-6(2), 6-2.
Pavlyuchenkova has never got further than the Round of 16 in Stuttgart; she managed that in 2014, losing to Maria Sharapova 6-4, 6-3, and in 2011, losing to Vera Zvonareva 3-6, 6-4, 6-2.
This is Rybarikova's first appearance in Stuttgart in nine years; in 2009 she lost in the Round of 32 to Gisela Dulko, 6-3, 6-3.