2021 European Open – Singles

Ugo Humbert was the defending champion, but chose not to participate this year.

Jannik Sinner won the title, defeating Diego Schwartzman in the final, 6–2, 6–2.

Seeds
The top four seeds received a bye into the second round. • #🇮🇹 Jannik Sinner (champion)

• #🇦🇷 Diego Schwartzman (final)

• # Cristian Garín (second round)

• #🇪🇸 Roberto Bautista Agut (second round)

• #🇺🇸 Reilly Opelka (first round)

• #🇦🇺 Alex de Minaur (first round)

• # Lloyd Harris (semifinals)

• #🇷🇸 Dušan Lajović (second round)

Seeds
• # 🇺🇸 Jenson Brooksby (qualified)

• # 🇺🇸 Brandon Nakashima (qualified)

• # 🇪🇸 Roberto Carballés Baena (qualifying competition)

• # 🇮🇹 Andreas Seppi (qualifying competition)

• # Henri Laaksonen (qualified)

• # 🇫🇷 Pierre-Hugues Herbert (qualifying competition)

• # 🇦🇹 Dennis Novak (qualified)

• # 🇸🇰 Norbert Gombos (qualifying competition)

Qualifiers
• # 🇺🇸 Jenson Brooksby

• # 🇺🇸 Brandon Nakashima

• # Henri Laaksonen

• # 🇦🇹 Dennis Novak