2021 Hamburg European Open – Men's singles
| Men's singles | |
|---|---|
| 2021 Hamburg European Open | |
| Champion | Pablo Carreño Busta |
| Runner-up | Filip Krajinović |
| Score | 6–2, 6–4 |
| Draw | 28 (6Q / 4WC) |
| Seeds | 8 |
Andrey Rublev was the defending champion, but chose to not defend his title as he and other Russian Olympic athletes were sent to Yuzhno-Sakhalinsk for training sessions.
Pablo Carreño Busta won his maiden ATP Tour 500 singles title, defeating Filip Krajinović in the final, 6–2, 6–4.