# 2021 Challenger de Santiago – Singles

Hugo Dellien was the defending champion but chose not to defend his title.
Sebastián Báez won the title after defeating Marcelo Tomás Barrios Vera 6–3, 7–6$^{(7–4)}$ in the final.

## Seeds

* Roberto Carballés Baena (second round)
* Andrej Martin (second round)
* Pedro Sousa (second round)
* Facundo Bagnis (withdrew)
* Jozef Kovalík (first round)
* Daniel Altmaier (second round)
* Kimmer Coppejans (second round)
* Alejandro Tabilo (first round)

## Draw
### Key

* Q = Qualifier
* WC = Wild card
* LL = Lucky loser
* Alt = Alternate
* SE = Special exempt
* PR = Protected ranking
* ITF = ITF entry
* JE = Junior exempt
* w/o = Walkover
* r = Retired
* d = Defaulted
* SR = Special ranking

### Finals

| Semifinals | Semifinals | Semifinals | Final | Final | Final |
| Marcelo Tomás Barrios Vera | 7$^7$ | 1 | | | |
| Felipe Meligeni Alves | 6$^5$ | 1$^r$ | | | |
| Felipe Meligeni Alves | 6$^5$ | 1$^r$ | Marcelo Tomás Barrios Vera | 3 | 6$^4$ |
| | | | Sebastián Báez | 6 | 7$^7$ |
| Sebastián Báez | 6 | 7$^7$ | Sebastián Báez | 6 | 7$^7$ |
| Juan Pablo Varillas | 1 | 6$^3$ | | | |

### Top half

| First round | First round | First round | First round | First round | Second round | Second round | Second round | Second round | Second round | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Semifinals | Semifinals | Semifinals |
| 1 | R Carballés Baena | 2 | 6 | 7$^7$ | | | | | | | | | | | | |
| | T Bellucci | 6 | 2 | 6$^0$ | 1 | R Carballés Baena | 6 | 6$^5$ | 6$^8$ | | | | | | | |
| WC | G Lama | 6 | 6 | | WC | G Lama | 2 | 7$^7$ | 7$^{10}$ | | | | | | | |
| | TM Etcheverry | 4 | 2 | | | | | | | WC | G Lama | 6$^4$ | 6$^5$ | | | |
| | MT Barrios Vera | 4 | 6 | 7$^7$ | | | | | | | MT Barrios Vera | 7$^7$ | 7$^7$ | | | |
| | C Lindell | 6 | 1 | 6$^4$ | | MT Barrios Vera | 6 | 6 | | | | | | | | |
| | O Luz | 3 | 1 | | 7 | K Coppejans | 4 | 4 | | | | | | | | |
| 7 | K Coppejans | 6 | 6 | | | | | | | | | | | MT Barrios Vera | 7$^7$ | 1 |
| 3 | P Sousa | 6 | 6 | | | | | | | | | | | F Meligeni Alves | 6$^5$ | 1$^r$ |
| LL | R Matos | 4 | 3 | | 3 | P Sousa | 4 | 2 | | | | | | | | |
| | F Meligeni Alves | 5 | 6 | 7 | | F Meligeni Alves | 6 | 6 | | | | | | | | |
| Q | J Menezes | 7 | 3 | 5 | | | | | | | F Meligeni Alves | 6 | 7 | | | |
| | E Benchetrit | 6 | 6 | | | | | | | Q | N Kicker | 1 | 5 | | | |
| | G Blancaneaux | 4 | 4 | | | E Benchetrit | 2 | 4 | | | | | | | | |
| Q | N Kicker | 6 | 6 | | Q | N Kicker | 6 | 6 | | | | | | | | |
| 5 | J Kovalík | 2 | 3 | | | | | | | | | | | | | |

### Bottom half

| First round | First round | First round | First round | First round | Second round | Second round | Second round | Second round | Second round | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Semifinals | Semifinals | Semifinals |
| 6 | D Altmaier | 6 | 6 | | | | | | | | | | | | | |
| | G Andreozzi | 4 | 3 | | 6 | D Altmaier | 4 | 6 | 3 | | | | | | | |
| Alt | C Ugo Carabelli | 6 | 6 | | Alt | C Ugo Carabelli | 6 | 3 | 6 | | | | | | | |
| Q | M Cuevas | 4 | 0 | | | | | | | Alt | C Ugo Carabelli | 2 | 1 | | | |
| WC | H Rune | 2 | 4 | | | | | | | | S Báez | 6 | 6 | | | |
| | S Báez | 6 | 6 | | | S Báez | 7 | 6 | | | | | | | | |
| | A Collarini | 4 | 4 | | Q | G Villanueva | 5 | 2 | | | | | | | | |
| Q | G Villanueva | 6 | 6 | | | | | | | | | | | S Báez | 6 | 7$^7$ |
| 8 | A Tabilo | 3 | 2 | | | | | | | | | | | JP Varillas | 1 | 6$^3$ |
| WC | N Jarry | 6 | 6 | | WC | N Jarry | 6 | 6 | | | | | | | | |
| | N Álvarez | 3 | 6 | 6 | | N Álvarez | 3 | 4 | | | | | | | | |
| | P Sakamoto | 6 | 4 | 3 | | | | | | WC | N Jarry | 2 | 4 | | | |
| | JP Varillas | 6 | 3 | 7 | | | | | | | JP Varillas | 6 | 6 | | | |
| | R Olivo | 4 | 6 | 5 | | JP Varillas | 6 | 6$^9$ | 6 | | | | | | | |
| | G Oliveira | 6$^2$ | 5 | | 2 | A Martin | 4 | 7$^{11}$ | 4 | | | | | | | |
| 2 | A Martin | 7$^7$ | 7 | | | | | | | | | | | | | |