2021 Hamburg European Open – Men's singles

Men's singles
2021 Hamburg European Open
Champion Pablo Carreño Busta
Runner-up Filip Krajinović
Score6–2, 6–4
Draw28 (6Q / 4WC)
Seeds8

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.