2021 Erste Bank Open
The 2021 Erste Bank Open was a men's tennis tournament played on indoor hard courts. It was the 47th edition of the event, and part of the ATP Tour 500 Series of the 2021 ATP Tour. It was held at the Wiener Stadthalle in Vienna, Austria, from 25 until 31 October 2021. Second-seeded Alexander Zverev won the singles title.
Finals
Singles
Alexander Zverev def. Frances Tiafoe, 7–5, 6–4Doubles
Juan Sebastián Cabal / Robert Farah def. Rajeev Ram / Joe Salisbury, 6–4, 6–2Singles main-draw entrants
Seeds
- Rankings are as of October 18, 2021
Other entrants
The following players received wildcards into the singles main draw:The following player received entry using a special exempt:
The following players received entry from the qualifying draw:
The following player received entry as a lucky loser:
Withdrawals
;Before the tournament- Cristian Garín → replaced by Dominik Koepfer
- Ugo Humbert → replaced by Márton Fucsovics
Doubles main-draw entrants
Seeds
- Rankings are as of 18 October 2021
Other entrants
The following pairs received wildcards into the doubles main draw:The following pair received entry from the qualifying draw:
The following pair received entry as lucky losers:
Withdrawals
;Before the tournament- Cristian Garín / Cameron Norrie → replaced by Sander Gillé / Dominik Koepfer
- Kevin Krawietz / Horia Tecău → replaced by Lloyd Harris / Horia Tecău