2021 Porto Open – Singles

This was the first edition of the tournament.

Altuğ Çelikbilek won the title after defeating Quentin Halys 6–2, 6–1 in the final.

Seeds
• # 🇧🇷 Thiago Seyboth Wild (second round)

• # 🇮🇳 Prajnesh Gunneswaran (second round)

• # 🇪🇨 Emilio Gómez (semifinals)

• # Alejandro Tabilo (first round)

• # Frederico Ferreira Silva (second round, retired)

• # 🇯🇵 Go Soeda (first round)

• # 🇦🇺 Thanasi Kokkinakis (second round)

• # 🇺🇿 Denis Istomin (second round)