2021 Swiss Open Gstaad

The 2021 Swiss Open Gstaad was a men's tennis tournament played on outdoor clay courts. It was the 53rd edition of the Swiss Open, and part of the ATP Tour 250 Series of the 2021 ATP Tour. It took place at the Roy Emerson Arena in Gstaad, Switzerland, from 19 July through 25 July 2021.

Singles

 * 🇳🇴 Casper Ruud def. 🇫🇷 Hugo Gaston, 6–3, 6–2

Doubles

 * Marc-Andrea Hüsler / Dominic Stricker def. 🇵🇱 Szymon Walków / 🇵🇱 Jan Zieliński, 6–1, 7–6(9–7)

Prize money

 * per team

Seeds

 * 1 Rankings are as of July 12, 2021

Other entrants
The following players received wildcards into the main draw:
 * Johan Nikles
 * Leandro Riedi
 * Dominic Stricker

The following players received entry from the qualifying draw:
 * 🇧🇪 Zizou Bergs
 * Sandro Ehrat
 * 🇨🇿 Vít Kopřiva
 * 🇩🇪 Oscar Otte

The following players received entry as lucky losers:
 * 🇫🇷 Enzo Couacaud
 * 🇵🇱 Kacper Żuk

Withdrawals

 * Before the tournament
 * 🇦🇷 Facundo Bagnis → replaced by 🇦🇷 Juan Ignacio Londero
 * 🇪🇸 Roberto Carballés Baena → replaced by Tallon Griekspoor
 * 🇦🇷 Federico Coria → replaced by 🇫🇷 Hugo Gaston
 * 🇸🇰 Norbert Gombos → replaced by 🇦🇹 Dennis Novak
 * 🇩🇪 Yannick Hanfmann → replaced by 🇵🇱 Kacper Żuk
 * 🇩🇪 Philipp Kohlschreiber → replaced by 🇫🇷 Enzo Couacaud
 * 🇵🇱 Kamil Majchrzak → replaced by Marc-Andrea Hüsler
 * 🇦🇹 Dominic Thiem → replaced by 🇫🇷 Arthur Rinderknech
 * 🇫🇷 Jo-Wilfried Tsonga → replaced by 🇦🇺 Marc Polmans
 * 🇪🇸 Fernando Verdasco → replaced by 🇧🇷 Thiago Seyboth Wild

Retirements

 * Tallon Griekspoor
 * Marc-Andrea Hüsler

Seeds

 * 1 Rankings are as of 12 July 2021.

Other entrants
The following pairs received wildcards into the doubles main draw:
 * Marc-Andrea Hüsler / Dominic Stricker
 * Jakub Paul / Leandro Riedi

Withdrawals

 * Before the tournament
 * 🇵🇱 Kamil Majchrzak / 🇵🇱 Szymon Walków → replaced by 🇵🇱 Szymon Walków / 🇵🇱 Jan Zieliński
 * 🇸🇪 Elias Ymer / 🇸🇪 Mikael Ymer → replaced by 🇩🇪 Dustin Brown / 🇦🇹 Tristan-Samuel Weissborn
 * 🇩🇪 Yannick Hanfmann / 🇦🇺 Marc Polmans → replaced by 🇧🇪 Zizou Bergs / Tallon Griekspoor
 * During the tournament
 * 🇧🇪 Zizou Bergs / Tallon Griekspoor

Retirements

 * Sander Arends / David Pel