Ugo Humbert defeated Andrey Rublev in the final 6–3, 7–6(7–4), to win the singles tennis title at the 2021 Halle Open.

Humbert's win earned him his third career ATP Tour singles title and his first ATP 500 victory, and also made him the first French player to win the tournament since Henri Leconte won the inaugural edition in 1993.

[1][2] Both Humbert and Rublev were contesting their first career final on grass.

[3] Roger Federer was the defending champion from when the event was last held in 2019,[4] but he lost in the second round to Félix Auger-Aliassime.

[5]