2021 Winners Open

The 2021 WTA Romanian Open, known as the Winners Open due to sponsorship reasons, was a professional women's tennis tournament played on outdoor clay courts at the Winners Sports Club. It was the 1st edition of the tournament held in the city of Cluj-Napoca and was a part of the 2021 WTA Tour.

Singles

 * 🇩🇪 Andrea Petkovic def. 🇪🇬 Mayar Sherif, 6–1, 6–1.

This was Petkovic's seventh WTA Tour singles title, and first since 2015.

Doubles

 * 🇷🇺 Natela Dzalamidze / Kaja Juvan def. 🇵🇱 Katarzyna Piter / 🇪🇬 Mayar Sherif, 6–3, 6–4.

This was the maiden WTA Tour title won by both Dzalamidze and Juvan.

Seeds

 * Rankings are as of July 26, 2021.

Other entrants
The following players received wildcards into the main draw:
 * Alex Eala
 * 🇷🇴 Elena-Gabriela Ruse
 * 🇷🇴 Briana Szabó
 * 🇷🇴 Evelyne Tiron

The following player received entry using a protected ranking:
 * 🇩🇪 Andrea Petkovic

The following players received entry from the qualifying draw:
 * 🇷🇴 Alexandra Dulgheru
 * Jana Fett
 * 🇷🇸 Aleksandra Krunić
 * 🇦🇺 Seone Mendez
 * 🇦🇷 Paula Ormaechea
 * 🇭🇺 Panna Udvardy

Withdrawals

 * Before the tournament
 * 🇭🇺 Tímea Babos → replaced by 🇵🇱 Katarzyna Kawa
 * 🇷🇴 Irina-Camelia Begu → replaced by 🇸🇰 Viktória Kužmová
 * 🇮🇹 Elisabetta Cocciaretto → replaced by 🇷🇴 Mihaela Buzărnescu
 * 🇰🇿 Zarina Diyas → replaced by 🇷🇴 Jaqueline Cristian
 * 🇮🇹 Sara Errani → replaced by 🇸🇰 Kristína Kučová
 * Viktorija Golubic → replaced by 🇪🇬 Mayar Sherif
 * Polona Hercog → replaced by 🇸🇰 Anna Karolína Schmiedlová
 * 🇨🇿 Tereza Martincová → replaced by 🇺🇦 Lesia Tsurenko
 * 🇮🇹 Jasmine Paolini → replaced by 🇭🇺 Réka Luca Jani
 * Arantxa Rus → replaced by 🇹🇷 Çağla Büyükakçay
 * 🇷🇴 Patricia Maria Țig → replaced by 🇪🇸 Lara Arruabarrena

Seeds

 * Rankings are as of July 26, 2021.

Other entrants
The following pairs received wildcards into the doubles main draw:
 * 🇷🇴 Ana Bogdan / 🇷🇴 Jaqueline Cristian
 * 🇷🇴 Miriam Bulgaru / 🇷🇴 Irina Fetecău

The following pair received entry using a protected ranking:
 * 🇷🇺 Alexandra Panova / 🇩🇪 Julia Wachaczyk

Withdrawals

 * Before the tournament
 * 🇷🇴 Irina-Camelia Begu / 🇷🇴 Andreea Mitu → replaced by 🇪🇸 Lara Arruabarrena / 🇷🇴 Andreea Mitu
 * 🇭🇺 Anna Bondár / 🇭🇺 Fanny Stollár → replaced by 🇵🇱 Katarzyna Piter / 🇪🇬 Mayar Sherif
 * 🇰🇿 Anna Danilina / 🇳🇴 Ulrikke Eikeri → replaced by 🇭🇺 Anna Bondár / 🇳🇴 Ulrikke Eikeri
 * 🇸🇰 Viktória Kužmová / Arantxa Rus → replaced by 🇷🇺 Alena Fomina / 🇷🇺 Ekaterina Yashina
 * 🇩🇪 Vivian Heisen / 🇵🇱 Alicja Rosolska → replaced by 🇸🇰 Viktória Kužmová / 🇵🇱 Alicja Rosolska
 * Ekaterine Gorgodze / 🇵🇱 Paula Kania-Choduń → replaced by 🇷🇴 Oana Georgeta Simion / 🇷🇴 Gabriela Talabă