2021 Rio Tennis Classic

Country	Player	Rank1	Seed
BRA	Thiago Seyboth Wild	131	1
ARG	Nicolás Kicker	230	2
ARG	Juan Pablo Ficovich	232	3
BRA	Matheus Pucinelli de Almeida	286	4
DOM	Roberto Cid Subervi	296	5
BRA	Orlando Luz	300	6
SRB	Peđa Krstin	311	7
JPN	Kaichi Uchida	316	8

• ¹ Rankings are as of 6 December 2021.^[1]

The following players received wildcards into the singles main draw:

• Gabriel Décamps
• Lorenzo Esquici
• Wilson Leite

The following player received entry into the singles main draw using a protected ranking:

• Guilherme Clezar

The following player received entry into the singles main draw as a special exempt:

• Igor Marcondes

The following player received entry into the singles main draw as an alternate:

• Mateus Alves

The following players received entry from the qualifying draw:

• Nicolás Barrientos
• Luca Castelnuovo
• Rafael Matos
• José Pereira

The following players received entry as lucky losers:

• Roy Smith
• Federico Zeballos

• Kaichi Uchida def. Nicolás Álvarez Varona 3–6, 6–3, 7–6^(7–3).

• Orlando Luz / Rafael Matos def. James Cerretani / Fernando Romboli 6–3, 7–6^(7–2).