2021 J&T Banka Ostrava Open

The 2021 J&T Banka Ostrava Open was a WTA tournament organised for female professional tennis players on indoor hard courts. It was the 2nd edition of the event on the 2021 WTA Tour, primarily organised due to the cancellation of the Asian tournaments during the 2021 season, because of the ongoing COVID-19 pandemic. The event took place at the Ostrava Arena in Ostrava, Czech Republic, from 20 through 26 September 2021.

Singles

 * 🇪🇪 Anett Kontaveit def. Maria Sakkari, 6–2, 7–5

Doubles

 * 🇮🇳 Sania Mirza / 🇨🇳 Zhang Shuai def. 🇺🇸 Kaitlyn Christian / 🇳🇿 Erin Routliffe 6–3, 6–2

Seeds

 * Rankings are as of September 13, 2021.

Other entrants
The following players received wildcards into the singles main draw:
 * 🇫🇷 Caroline Garcia
 * 🇨🇿 Tereza Martincová
 * Jeļena Ostapenko
 * 🇨🇿 Kateřina Siniaková

The following players received entry from the qualifying draw:
 * 🇫🇷 Océane Dodin
 * 🇫🇷 Fiona Ferro
 * Ana Konjuh
 * 🇵🇱 Magda Linette
 * 🇷🇺 Anastasia Potapova
 * 🇷🇺 Anastasia Zakharova

The following players received entry as lucky losers:
 * 🇷🇺 Anna Blinkova
 * 🇷🇺 Varvara Gracheva

Withdrawals

 * Before the tournament
 * 🇨🇿 Barbora Krejčíková → replaced by 🇨🇳 Zhang Shuai
 * 🇧🇪 Elise Mertens → replaced by 🇷🇺 Varvara Gracheva
 * Petra Martić → replaced by 🇪🇸 Sara Sorribes Tormo
 * 🇨🇿 Karolína Muchová → replaced by 🇷🇺 Anna Blinkova
 * 🇨🇿 Karolína Plíšková → replaced by Jil Teichmann
 * 🇺🇦 Elina Svitolina → replaced by 🇷🇴 Sorana Cîrstea

Seeds

 * 1 Rankings as of September 13, 2021.

Withdrawals

 * Before the tournament
 * 🇷🇺 Ekaterina Alexandrova / Stefanie Vögele → replaced by 🇮🇳 Rutuja Bhosale / 🇬🇧 Emily Webley-Smith
 * 🇷🇺 Natela Dzalamidze / 🇷🇺 Kamilla Rakhimova → replaced by 🇷🇺 Natela Dzalamidze / 🇷🇺 Yana Sizikova