2021 Rio Tennis Classic – Singles

Carlos Berlocq was the defending champion but chose not to defend his title.

Kaichi Uchida won the title after defeating Nicolás Álvarez Varona 3–6, 6–3, 7–6(7–3) in the final.

Seeds
• # 🇧🇷 Thiago Seyboth Wild (quarterfinals)

• # 🇦🇷 Nicolás Kicker (semifinals)

• # 🇦🇷 Juan Pablo Ficovich (first round)

• # 🇧🇷 Matheus Pucinelli de Almeida (withdrew)

• # 🇩🇴 Roberto Cid Subervi (first round, retired)

• # 🇧🇷 Orlando Luz (first round)

• # 🇷🇸 Peđa Krstin (first round)

• # 🇯🇵 Kaichi Uchida (champion)