| Singles | |
|---|---|
| 2021 Challenger de Buenos Aires | |
| Champion |  Sebastián Báez |
| Runner-up |  Thiago Monteiro |
| Score | 6–4, 6–0 |
Sumit Nagal was the defending champion [1] but chose not to defend his title.
Sebastián Báez won the title after defeating Thiago Monteiro 6–4, 6–0 in the final.
Thiago Monteiro (final) Juan Manuel Cerúndolo (semifinals) Francisco Cerúndolo (semifinals)
Juan Pablo Varillas (quarterfinals)
Hugo Dellien (quarterfinals) Thiago Seyboth Wild (first round) Sebastián Báez (champion) Tomás Martín Etcheverry (quarterfinals)| Semifinals | Final | ||||||||||||
| 1 | Thiago Monteiro | 6 | 2 | 6 | |||||||||
| 3 | Francisco Cerúndolo | 1 | 6 | 3 | |||||||||
| 1 | Thiago Monteiro | 4 | 0 | ||||||||||
| 7 | Sebastián Báez | 6 | 6 | ||||||||||
| 7 | Sebastián Báez | 6 | 6 | ||||||||||
| 2 | Juan Manuel Cerúndolo | 1 | 2 | ||||||||||
| First round | Second round | Quarterfinals | Semifinals | ||||||||||||||||||||||||
| 1 | T Monteiro | 79 | 3 | 6 | |||||||||||||||||||||||
| H Casanova | 67 | 6 | 2 | 1 | T Monteiro | 6 | 6 | ||||||||||||||||||||
| N Kicker | 6 | 2 | 6 | N Kicker | 2 | 3 | |||||||||||||||||||||
| N Álvarez | 3 | 6 | 3 | 1 | T Monteiro | 6 | 3 | 7 | |||||||||||||||||||
| TA Tirante | 4 | 0 | 8 | TM Etcheverry | 4 | 6 | 5 | ||||||||||||||||||||
| R Olivo | 6 | 6 | R Olivo | 6 | 61 | 4 | |||||||||||||||||||||
| Q | Ignacio Monzón | 0 | 3 | 8 | TM Etcheverry | 3 | 77 | 6 | |||||||||||||||||||
| 8 | TM Etcheverry | 6 | 6 | 1 | T Monteiro | 6 | 2 | 6 | |||||||||||||||||||
| 3 | F Cerúndolo | 4 | 6 | 6 | 3 | F Cerúndolo | 1 | 6 | 3 | ||||||||||||||||||
| C Ugo Carabelli | 6 | 1 | 4 | 3 | F Cerúndolo | 7 | 6 | ||||||||||||||||||||
| JP Ficovich | 77 | 78 | JP Ficovich | 5 | 2 | ||||||||||||||||||||||
 N Sánchez Izquierdo | 61 | 66 | 3 | F Cerúndolo | 6 | 6 | |||||||||||||||||||||
| Q |  M Cuevas | 2 | 6 | 6 | Q | M Cuevas | 1 | 1 | |||||||||||||||||||
| Q | F Comesaña | 6 | 3 | 2 | Q | M Cuevas | 77 | 7 | |||||||||||||||||||
| WC | M Navone | 3 | 6 | 6 | WC | M Navone | 60 | 5 | |||||||||||||||||||
| 6 | T Seyboth Wild | 6 | 1 | 2 | |||||||||||||||||||||||
| First round | Second round | Quarterfinals | Semifinals | ||||||||||||||||||||||||
| 7 | S Báez | 3 | 6 | 6 | |||||||||||||||||||||||
| P Cachin | 6 | 2 | 3 | 7 | S Báez | 6 | 6 | ||||||||||||||||||||
| Q | C Gómez-Herrera | 3 | 4 | JI Londero | 3 | 4 | |||||||||||||||||||||
| JI Londero | 6 | 6 | 7 | S Báez | 7 | 6 | |||||||||||||||||||||
| S Rodríguez Taverna | 6 | 1 | 4 | JP Varillas | 5 | 2 | |||||||||||||||||||||
| WC | RA Burruchaga | 4 | 4r | S Rodríguez Taverna | 4 | 2 | |||||||||||||||||||||
 N Hardt | 3 | 6 | 2 | 4 | JP Varillas | 6 | 6 | ||||||||||||||||||||
| 4 | JP Varillas | 6 | 3 | 6 | 7 | S Báez | 6 | 6 | |||||||||||||||||||
| 5 | H Dellien | 4 | 6 | 6 | 2 | JM Cerúndolo | 1 | 2 | |||||||||||||||||||
| F Díaz Acosta | 6 | 0 | 1 | 5 | H Dellien | 3 | 7 | 78 | |||||||||||||||||||
| WC | JB Torres | 2 | 4 | F Meligeni Alves | 6 | 5 | 66 | ||||||||||||||||||||
| F Meligeni Alves | 6 | 6 | 5 | H Dellien | 6 | 5 | 65 | ||||||||||||||||||||
| GA Olivieri | 2 | 6 | 5 | 2 | JM Cerúndolo | 2 | 7 | 77 | |||||||||||||||||||
| A Collarini | 6 | 4 | 7 | A Collarini | 4 | 6 | 4 | ||||||||||||||||||||
| G Andreozzi | 4 | 2 | 2 | JM Cerúndolo | 6 | 3 | 6 | ||||||||||||||||||||
| 2 | JM Cerúndolo | 6 | 6 | ||||||||||||||||||||||||
Sebastian Korda, the son of 1998 men's singles champion Petr Korda, won the boys' singles tennis title at the 2018 Australian Open, defeating Tseng Chun-hsin in the final, 7–6(8–6), 6–4.
Hugo Gaston and Clément Tabur won the boys' doubles tennis title at the 2018 Australian Open, defeating Rudolf Molleker and Henri Squire in the final, 6–2, 6–2.
Tseng Chun-hsin won the boys' singles tennis title at the 2018 French Open, defeating Sebastián Báez in the final, 7–6(7–5), 6–2.
Nikoloz Basilashvili was the defending champion and successfully defended his title, defeating Andrey Rublev in the final, 7–5, 4–6, 6–3. En route to doing so, Basilashvili saved two match points against Alexander Zverev in the semifinals.
Pablo Andújar was the defending champion but chose not to defend his title.
Cristian Garín was the defending champion but chose not to defend his title.
Guido Andreozzi was the defending champion but chose not to defend his title.
Thiago Monteiro was the defending champion and successfully defended his title, defeating Marco Cecchinato 7–6(7–3), 6–7(6–8), 7–5 in the final.
Cristian Garín was the defending champion, but chose not to defend his title.
Diego Schwartzman defeated Francisco Cerúndolo in the final, 6–1, 6–2 to win the men's singles tennis title at the 2021 Argentina Open.
Andrey Rublev was the defending champion, but chose to not defend his title as he and other Russian Olympic athletes were sent to Yuzhno-Sakhalinsk for training sessions.
Sebastián Báez was the defending champion but lost in the final to Juan Pablo Varillas.
Juan Pablo Varillas was the defending champion but lost in the quarterfinals to Marcelo Tomás Barrios Vera.
Hugo Dellien was the defending champion but lost in the quarterfinals to Juan Manuel Cerúndolo.
Francisco Cerúndolo was the defending champion but lost in the second round to Gonçalo Oliveira.
Jaume Munar was the defending champion but lost in the semifinals to Juan Ignacio Londero.
Francisco Cerúndolo was the defending champion but lost in the semifinals to Sebastián Báez.
This was the first edition of the tournament.
Sebastián Báez was the defending champion but chose not to defend his title.
Thiago Monteiro was the defending champion but lost in the quarterfinals to Lukas Neumayer.