2021 Platzmann-Sauerland Open – Singles

This was the first edition of the tournament.

Daniel Altmaier won the title after defeating Nicolás Jarry 7–6(7–1), 4–6, 6–3 in the final.

Seeds
• # 🇪🇸 Pablo Andújar (first round)

• # 🇪🇸 Pedro Martínez (first round)

• # 🇪🇸 Roberto Carballés Baena (second round, retired)

• # 🇩🇪 Daniel Altmaier (champion)

• # 🇧🇴 Hugo Dellien (withdrew)

• # 🇦🇷 Juan Manuel Cerúndolo (semifinals)

• # 🇷🇺 Roman Safiullin (second round)

• # Robin Haase (second round, withdrew)

• # 🇫🇷 Constant Lestienne (second round)