| Champ: |  Casper Ruud |
| Runner: |  Denis Shapovalov |
| Score: | 7–6(8–6), 6–4 |
| Draw: | 28 (4 / 3) |
| Seeds: | 8 |
| Edition: | 18th |
| Type: | singles doubles |
| Main Name: | Geneva Open |
| Before Year: | 2019 |
See main article: 2021 Geneva Open. Alexander Zverev was the defending champion from when the event was held in 2019, but chose not to defend his title.[1]
Casper Ruud won the title, defeating Denis Shapovalov in the final, 7–6(8–6), 6–4.
The top four seeds received a bye into the second round.