2021 İstanbul Cup

The 2021 İstanbul Cup (also known as the TEB BNP Paribas Tennis Championship İstanbul for sponsorship reasons) is a tennis tournament played on outdoor clay courts. It is the 14th edition of the İstanbul Cup, and part of the WTA International tournaments of the 2021 WTA Tour. It took place in Istanbul, Turkey, from 19 through 25 April 2021.

Singles

 * 🇷🇴 Sorana Cîrstea def. 🇧🇪 Elise Mertens, 6–1, 7–6(7-3)

Doubles

 * 🇷🇺 Veronika Kudermetova / 🇧🇪 Elise Mertens def. 🇯🇵 Nao Hibino / 🇯🇵 Makoto Ninomiya, 6–1, 6–1.

Seeds

 * Rankings are as of April 12, 2021.

Other entrants
The following players received wildcard s into the singles main draw:
 * 🇹🇷 Çağla Büyükakçay
 * Ana Konjuh
 * 🇧🇪 Elise Mertens
 * 🇷🇺 Vera Zvonareva

The following players received entry from the qualifying draw:
 * 🇪🇸 Lara Arruabarrena
 * 🇪🇸 Cristina Bucșa
 * 🇷🇺 Anastasia Gasanova
 * Tereza Mrdeža
 * 🇪🇸 Nuria Párrizas Díaz
 * 🇷🇺 Kamilla Rakhimova

The following player received entry as a lucky loser:
 * 🇦🇹 Barbara Haas

Withdrawals

 * Before the tournament
 * 🇫🇷 Alizé Cornet → replaced by 🇰🇿 Zarina Diyas
 * 🇷🇺 Svetlana Kuznetsova → replaced by 🇨🇿 Kateřina Siniaková
 * 🇵🇱 Magda Linette → replaced by 🇯🇵 Nao Hibino
 * 🇰🇿 Yulia Putintseva → replaced by 🇮🇹 Sara Errani
 * Anastasija Sevastova → replaced by 🇺🇦 Marta Kostyuk
 * 🇪🇸 Sara Sorribes Tormo → replaced by 🇷🇺 Anastasia Potapova
 * Jil Teichmann → replaced by Viktorija Golubic
 * 🇷🇴 Patricia Maria Țig → replaced by 🇷🇴 Ana Bogdan
 * 🇨🇳 Zheng Saisai → replaced by 🇦🇹 Barbara Haas

Retirements

 * 🇫🇷 Fiona Ferro

Seeds

 * 1 Rankings as of April 12, 2021.

Other entrants
The following pairs received wildcard s into the doubles main draw:
 * 🇹🇷 Çağla Büyükakçay / 🇹🇷 Pemra Özgen
 * 🇷🇺 Elena Vesnina / 🇷🇺 Vera Zvonareva

The following pairs received entry using protected rankings:
 * Viktorija Golubic / 🇷🇺 Alexandra Panova
 * Beatrice Gumulya / Jessy Rompies

Withdrawals

 * Before the tournament
 * Arantxa Rus / Tamara Zidanšek → replaced by  Beatrice Gumulya /  Jessy Rompies