| 2021 Rio Tennis Classic | |
|---|---|
| Date | 13–19 December |
| Edition | 2nd |
| Draw | 32S / 16D |
| Surface | Hard |
| Location | Rio de Janeiro, Brazil |
| Champions | |
| Singles | |
 Kaichi Uchida | |
| Doubles | |
 Orlando Luz / Rafael Matos | |
The 2021 Rio Tennis Classic was a professional tennis tournament played on hard courts. It was the second edition of the tournament which was part of the 2021 ATP Challenger Tour. It took place in Rio de Janeiro, Brazil from 13 to 19 December 2021.
| Country | Player | Rank1 | Seed |
|---|---|---|---|
| BRA | Thiago Seyboth Wild | 131 | 1 |
 ARG | Nicolás Kicker | 230 | 2 |
| ARG | Juan Pablo Ficovich | 232 | 3 |
| BRA | |||
 DOM | Roberto Cid Subervi | 296 | 5 |
| BRA | Orlando Luz | 300 | 6 |
 SRB | Peđa Krstin | 311 | 7 |
| JPN | Kaichi Uchida | 316 | 8 |
The following players received wildcards into the singles main draw:
Gabriel Décamps Lorenzo Esquici Wilson LeiteThe following player received entry into the singles main draw using a protected ranking:
The following player received entry into the singles main draw as a special exempt:
The following player received entry into the singles main draw as an alternate:
The following players received entry from the qualifying draw:
Nicolás Barrientos 
Luca Castelnuovo Rafael Matos José PereiraThe following players received entry as lucky losers:
Roy Smith
Federico Zeballos Kaichi Uchida def. 
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