2021 Mutua Madrid Open – Women's singles

Aryna Sabalenka defeated Ashleigh Barty in the final, 6–0, 3–6, 6–4 to win the women's singles tennis title at the 2021 Madrid Open. It was her 10th career WTA Tour singles title, and her first on clay.

Kiki Bertens was the defending champion from when the tournament was last held in 2019, but lost in the second round to Veronika Kudermetova.

Paula Badosa became the first Spaniard in the tournament's history to reach the semifinals.

Seeds
• 🇦🇺 Ashleigh Barty (final)

• 🇯🇵 Naomi Osaka (second round)

• 🇷🇴 Simona Halep (third round)

• 🇺🇦 Elina Svitolina (first round)

• 🇧🇾 Aryna Sabalenka (champion)

• 🇨🇿 Karolína Plíšková (second round)

• Kiki Bertens (second round)

• Belinda Bencic (quarterfinals)

• 🇨🇿 Petra Kvitová (quarterfinals)

• 🇪🇸 Garbiñe Muguruza (withdrew)

• 🇺🇸 Jennifer Brady (third round)

• 🇧🇾 Victoria Azarenka (second round, withdrew)

• 🇧🇪 Elise Mertens (quarterfinals, retired)

• 🇵🇱 Iga Świątek (third round)

• 🇬🇧 Johanna Konta (second round)

• Maria Sakkari (third round)

Seeds
• # Anastasija Sevastova (qualified)

• # 🇫🇷 Kristina Mladenovic (qualified)

• # 🇩🇪 Laura Siegemund (qualified)

• # 🇫🇷 Alizé Cornet (first round)

• # 🇲🇪 Danka Kovinić (qualifying competition, lucky loser)

• # Hsieh Su-wei (qualifying competition, lucky loser)

• # 🇪🇪 Kaia Kanepi (first round)

• # 🇨🇿 Kateřina Siniaková (first round)

• # 🇧🇪 Alison Van Uytvanck (first round)

• # 🇬🇧 Heather Watson (first round)

• # 🇺🇸 Bernarda Pera (qualified)

• # 🇨🇦 Leylah Annie Fernandez (first round)

• # Polona Hercog (qualifying competition, lucky loser)

• # 🇷🇴 Irina-Camelia Begu (qualified)

• # 🇷🇺 Anastasia Potapova (qualifying competition)

• # 🇺🇦 Marta Kostyuk (qualifying competition)

• # 🇦🇺 Ajla Tomljanović (qualified)

• # 🇯🇵 Misaki Doi (qualified)

• # Tamara Zidanšek (qualified)

• # 🇯🇵 Nao Hibino (qualifying competition)

• # Arantxa Rus (first round)

• # 🇷🇸 Nina Stojanović (qualified)

• # 🇰🇿 Zarina Diyas (qualifying competition)

• # 🇧🇾 Aliaksandra Sasnovich (qualifying competition)

Qualifiers
• # Anastasija Sevastova

• # 🇫🇷 Kristina Mladenovic

• # 🇩🇪 Laura Siegemund

• # 🇦🇺 Ajla Tomljanović

• # 🇯🇵 Misaki Doi

• # Tamara Zidanšek

• # 🇺🇦 Kateryna Kozlova

• # 🇷🇴 Ana Bogdan

• # 🇷🇺 Vera Zvonareva

• # 🇷🇴 Irina-Camelia Begu

• # 🇺🇸 Bernarda Pera

• # 🇷🇸 Nina Stojanović

Lucky losers
• # Hsieh Su-wei

• # 🇲🇪 Danka Kovinić

• # Polona Hercog

Seeds
The following are the seeded players. Seedings are based on WTA rankings as of 26 April 2021. Rankings and points before are as of 26 April 2021. † The player did not qualify for the tournament in 2019. Accordingly, this was her 16th best result deducted instead.

Other entrants
The following players received wildcards into the main draw:
 * 🇪🇸 Paula Badosa
 * 🇷🇴 Sorana Cîrstea
 * 🇦🇩 Victoria Jiménez Kasintseva
 * 🇪🇸 Sara Sorribes Tormo
 * 🇺🇸 Venus Williams

The following players received entry using a protected ranking:
 * 🇰🇿 Yaroslava Shvedova
 * 🇷🇺 Elena Vesnina

The following players received entry from the qualifying draw:
 * 🇷🇴 Irina-Camelia Begu
 * 🇷🇴 Ana Bogdan
 * 🇯🇵 Misaki Doi
 * 🇺🇦 Kateryna Kozlova
 * 🇫🇷 Kristina Mladenovic
 * 🇺🇸 Bernarda Pera
 * Anastasija Sevastova
 * 🇩🇪 Laura Siegemund
 * 🇷🇸 Nina Stojanović
 * 🇦🇺 Ajla Tomljanović
 * Tamara Zidanšek
 * 🇷🇺 Vera Zvonareva

The following players received entry as lucky losers:
 * Polona Hercog
 * Hsieh Su-wei
 * 🇲🇪 Danka Kovinić

Withdrawals

 * Before the tournament
 * 🇨🇦 Bianca Andreescu → replaced by 🇨🇳 Zheng Saisai
 * 🇺🇸 Danielle Collins → replaced by 🇵🇱 Magda Linette
 * 🇫🇷 Fiona Ferro → replaced by 🇷🇺 Elena Vesnina
 * 🇺🇸 Sofia Kenin → replaced by 🇺🇸 Shelby Rogers
 * 🇷🇺 Svetlana Kuznetsova → replaced by Polona Hercog
 * 🇪🇸 Garbiñe Muguruza → replaced by 🇲🇪 Danka Kovinić
 * 🇨🇿 Barbora Strýcová → replaced by 🇰🇿 Yaroslava Shvedova
 * Donna Vekić → replaced by 🇺🇸 Sloane Stephens
 * 🇺🇸 Serena Williams → replaced by Hsieh Su-wei
 * 🇺🇦 Dayana Yastremska → replaced by Jeļena Ostapenko


 * During the tournament
 * 🇧🇾 Victoria Azarenka

Retirements

 * 🇨🇿 Marie Bouzková
 * 🇧🇪 Elise Mertens