2021 Karlsruhe Open

The 2021 Karlsruhe Open (also known as the Liqui Moly Open for sponsorship reasons) was a professional tennis tournament played on outdoor clay courts. It was the 2nd edition of the tournament and part of the 2021 WTA 125K series, offering a total of $115,000 in prize money. It took place in Karlsruhe, Germany between 7 and 12 September 2021. The tournament did not take place in 2020 due to the COVID-19 pandemic.

Singles

 * 🇪🇬 Mayar Sherif def. 🇮🇹 Martina Trevisan, 6–3, 6–2

Doubles

 * 🇷🇴 Irina Bara / Ekaterine Gorgodze def. 🇵🇱 Katarzyna Piter / 🇪🇬 Mayar Sherif, 6–3, 2–6, [10–7]

Seeds

 * 1 Rankings as of 30 August 2021.

Other entrants
The following players received a wildcard into the singles main draw:
 * 🇩🇪 Sina Herrmann
 * 🇩🇪 Tatjana Maria
 * 🇩🇪 Nastasja Schunk
 * 🇩🇪 Alexandra Vecic

The following players qualified into the singles main draw:
 * 🇮🇹 Giulia Gatto-Monticone
 * 🇩🇪 Katharina Hobgarski
 * 🇩🇪 Yana Morderger
 * Tereza Mrdeža

Withdrawals

 * Before the tournament
 * 🇷🇴 Ana Bogdan → replaced by 🇦🇺 Maddison Inglis
 * 🇮🇹 Elisabetta Cocciaretto → replaced by 🇷🇴 Jaqueline Cristian
 * 🇷🇺 Varvara Gracheva → replaced by 🇦🇷 Paula Ormaechea
 * Polona Hercog → replaced by Ekaterine Gorgodze
 * 🇸🇰 Kristína Kučová → replaced by 🇸🇰 Rebecca Šramková
 * 🇺🇸 Varvara Lepchenko → replaced by 🇺🇸 Grace Min
 * 🇮🇹 Jasmine Paolini → replaced by 🇮🇹 Lucia Bronzetti
 * 🇪🇸 Nuria Párrizas Díaz → replaced by 🇺🇦 Katarina Zavatska
 * 🇨🇿 Kristýna Plíšková → replaced by 🇩🇪 Tamara Korpatsch
 * Arantxa Rus → replaced by 🇷🇺 Anastasia Gasanova
 * 🇷🇴 Elena-Gabriela Ruse → replaced by 🇭🇺 Dalma Gálfi
 * 🇧🇬 Viktoriya Tomova → replaced by 🇪🇸 Cristina Bucșa
 * 🇨🇳 Zhang Shuai → replaced by 🇵🇱 Katarzyna Kawa

Seeds

 * 1 Rankings as of 30 August 2021.

Other entrants
The following pair received a wildcard into the doubles main draw:
 * 🇩🇪 Nastasja Schunk / 🇩🇪 Alexandra Vecic