Sorana Cîrstea defeated
Elise Mertens in the final, 6–1, 7–6(7–3) to win the women's singles tennis title at the 2021
İstanbul Cup. This was Cîrstea's first title since
2008. Cîrstea did not drop a set throughout the tournament.
Patricia Maria Țig was the defending champion,[1] but she chose not to participate this year.
Bold denotes the mandatory tournaments (WTA 1000) † – Tournaments are affected by the
COVID-19 pandemic * – Tournaments are introduced due to the impact of the COVID-19 pandemic