2021 J&T Banka Ostrava Open – Singles

Aryna Sabalenka was the defending champion, but she chose not to compete this year.

Anett Kontaveit won her maiden WTA 500 title without dropping a set, defeating Maria Sakkari in the final, 6–2, 7–5.

Seeds
The top four seeds received a bye into the second round. • # 🇵🇱 Iga Świątek (semifinals)

• # 🇨🇿 Petra Kvitová (semifinals)

• # Belinda Bencic (quarterfinals)

• # Maria Sakkari (final)

• # 🇷🇺 Anastasia Pavlyuchenkova (second round)

• # 🇩🇪 Angelique Kerber (first round)

• # 🇰🇿 Elena Rybakina (quarterfinals)

• # 🇨🇿 Karolína Muchová (withdrew)

• # 🇪🇸 Paula Badosa (second round)

Seeds
• # 🇷🇺 Ekaterina Alexandrova (qualifying competition, retired)

• # 🇵🇱 Magda Linette (qualified)

• # 🇷🇺 Varvara Gracheva (qualifying competition, lucky loser)

• # 🇸🇪 Rebecca Peterson (first round)

• # Ana Konjuh (qualified)

• # 🇫🇷 Fiona Ferro (qualified)

• # 🇷🇺 Anastasia Potapova (qualified)

• # 🇺🇸 Bernarda Pera (qualifying competition)

• # 🇫🇷 Océane Dodin (qualified)

• # 🇷🇺 Anna Blinkova (qualifying competition, lucky loser)

• # 🇯🇵 Misaki Doi (first round)

• # 🇦🇺 Astra Sharma (qualifying competition)

Qualifiers
• # 🇷🇺 Anastasia Potapova

• # 🇵🇱 Magda Linette

• # 🇫🇷 Océane Dodin

• # 🇷🇺 Anastasia Zakharova

• # Ana Konjuh

• # 🇫🇷 Fiona Ferro

Lucky losers
• # 🇷🇺 Anna Blinkova

• # 🇷🇺 Varvara Gracheva