2021 Hamburg European Open

The 2021 Hamburg European Open was a combined men's and women's tennis tournament played on outdoor clay courts. It was the 115th edition of the event for the men and the 19th edition for the women, after last tournament being held in 2002. The tournament was classified as a WTA 250 tournament on the 2021 WTA Tour and as an ATP Tour 500 series on the 2021 ATP Tour (called the Hamburg Open). The tournament took place at the Am Rothenbaum in Hamburg, Germany between 6 and 18 July 2021. The event was scheduled a week earlier than the usual late July date to avoid scheduling conflicts with the 2020 Summer Olympics.

Men's singles

 * 🇪🇸 Pablo Carreño Busta def. 🇷🇸 Filip Krajinović, 6–2, 6–4

Women's singles

 * 🇷🇴 Elena-Gabriela Ruse def. 🇩🇪 Andrea Petkovic, 7–6(8–6), 6–4

This was Ruse's maiden WTA Tour singles title.

Men's doubles

 * 🇩🇪 Tim Pütz / 🇳🇿 Michael Venus def. 🇩🇪 Kevin Krawietz / 🇷🇴 Horia Tecău 6–3, 6–7(3–7), [10–8].

Women's doubles

 * 🇮🇹 Jasmine Paolini / Jil Teichmann def. 🇦🇺 Astra Sharma /  Rosalie van der Hoek 6–0, 6–4

Prize money

 * per team

Seeds

 * 1 Rankings are as of 28 June 2021.

Other entrants
The following players received wildcards into the main draw:
 * 🇩🇪 Daniel Altmaier
 * 🇩🇪 Philipp Kohlschreiber
 * 🇪🇸 Nicola Kuhn
 * Stefanos Tsitsipas

The following players received entry from the qualifying draw:
 * 🇩🇪 Maximilian Marterer
 * 🇸🇰 Alex Molčan
 * 🇧🇷 Thiago Seyboth Wild
 * 🇪🇸 Carlos Taberner
 * 🇵🇪 Juan Pablo Varillas
 * 🇨🇳 Zhang Zhizhen

The following players received entry as lucky losers:
 * 🇦🇷 Sebastián Báez
 * 🇮🇳 Sumit Nagal

Withdrawals

 * Before the tournament
 * 🇪🇸 Pablo Andújar → replaced by 🇮🇳 Sumit Nagal
 * 🇨🇦 Félix Auger-Aliassime → replaced by 🇫🇷 Lucas Pouille
 * Aljaž Bedene → replaced by 🇦🇷 Sebastián Báez
 * 🇭🇺 Márton Fucsovics → replaced by 🇮🇹 Gianluca Mager
 * 🇷🇺 Aslan Karatsev → replaced by 🇫🇷 Corentin Moutet
 * 🇮🇹 Lorenzo Sonego → replaced by Ričardas Berankis

Seeds

 * 1 Rankings are as of 28 June 2021.

Other entrants
The following pairs received wildcards into the doubles main draw:
 * 🇩🇪 Daniel Altmaier / 🇩🇪 Rudolf Molleker
 * Petros Tsitsipas / Stefanos Tsitsipas

The following pair received entry using protected ranking:
 * Ričardas Berankis / Lu Yen-hsun

The following pair received entry from the qualifying draw:
 * 🇮🇹 Alessandro Giannessi / 🇪🇸 Carlos Taberner

The following pair received entry as lucky losers:
 * Ruben Gonzales / 🇺🇸 Hunter Johnson

Withdrawals

 * Before the tournament
 * 🇬🇧 Luke Bambridge / 🇬🇧 Dominic Inglot → replaced by Ruben Gonzales / 🇺🇸 Hunter Johnson
 * 🇮🇹 Simone Bolelli / 🇦🇷 Máximo González → replaced by Ivan Sabanov /  Matej Sabanov
 * 🇧🇪 Sander Gillé / 🇧🇪 Joran Vliegen → replaced by 🇧🇪 Sander Gillé / 🇮🇳 Divij Sharan
 * 🇪🇸 Marcel Granollers / 🇦🇷 Horacio Zeballos → replaced by 🇺🇸 James Cerretani / 🇲🇽 Hans Hach Verdugo
 * 🇦🇹 Oliver Marach / 🇦🇹 Philipp Oswald → replaced by 🇮🇳 N.Sriram Balaji / Luca Margaroli
 * During the tournament
 * 🇷🇸 Filip Krajinović / 🇷🇸 Dušan Lajović

Seeds

 * 1 Rankings are as of 28 June 2021.

Other entrants
The following players received wildcards into the main draw:
 * 🇩🇪 Mona Barthel
 * 🇩🇪 Tamara Korpatsch
 * 🇩🇪 Jule Niemeier

The following players received entry from the qualifying draw:
 * 🇷🇺 Marina Melnikova
 * 🇱🇺 Mandy Minella
 * 🇷🇴 Elena-Gabriela Ruse
 * 🇩🇪 Anna Zaja

The following player received entry as a lucky loser:
 * 🇸🇰 Kristína Kučová

Withdrawals

 * Before the tournament
 * 🇪🇸 Paula Badosa → replaced by 🇨🇿 Kristýna Plíšková
 * 🇷🇴 Sorana Cîrstea → replaced by 🇷🇴 Irina Bara
 * 🇫🇷 Alizé Cornet → replaced by 🇸🇰 Kristína Kučová
 * 🇷🇺 Varvara Gracheva → replaced by 🇩🇪 Andrea Petkovic
 * 🇨🇿 Tereza Martincová → replaced by Ana Konjuh
 * 🇩🇪 Laura Siegemund → replaced by 🇧🇪 Ysaline Bonaventure
 * 🇪🇸 Sara Sorribes Tormo → replaced by 🇦🇺 Astra Sharma
 * 🇷🇴 Patricia Maria Țig → replaced by 🇵🇱 Magdalena Fręch
 * 🇨🇳 Zhang Shuai → replaced by 🇩🇪 Anna-Lena Friedsam

Seeds

 * 1 Rankings are as of 28 June 2021.

Other entrants
The following pair received a wildcard into the doubles main draw:
 * 🇩🇪 Eva Lys / 🇩🇪 Noma Noha Akugue