2021 Cleveland Open – Singles

Mikael Torpegaard was the defending champion but lost in the first round to Lucas Catarina.

Bjorn Fratangelo won the title after defeating Jenson Brooksby 7–5, 6–4 in the final.

Seeds
• # 🇦🇺 James Duckworth (first round)

• # 🇯🇵 Go Soeda (first round)

• # 🇪🇨 Emilio Gómez (semifinals)

• # Mikael Torpegaard (first round)

• # 🇺🇸 Mitchell Krueger (first round)

• # 🇨🇦 Brayden Schnur (second round)

• # 🇺🇸 Thai-Son Kwiatkowski (first round)

• # 🇩🇴 Roberto Cid Subervi (first round)