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 [World Tour 500 series|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, 6–4
Doubles
- Juan Sebastián Cabal / Robert [Farah |Robert Farah] def. Rajeev Ram / Joe Salisbury, 6–4, 6–2
Singles main-draw entrants
Seeds
- Rankings are as of October 18, 2021
Other entrants
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:
- Dominik Koepfer
Withdrawals
- 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 pair received entry from the qualifying draw:
The following pair received entry as lucky losers:
- Sander Gillé / Dominik Koepfer
Withdrawals
- Cristian Garín / Cameron Norrie → replaced by Sander Gillé / Dominik Koepfer
- Kevin Krawietz / Horia Tecău → replaced by Lloyd Harris / Horia Tecău