# 2021 Challenger Ciudad de Guayaquil – Singles

Francisco Cerúndolo was the defending champion but lost in the second round to Gonçalo Oliveira.
Alejandro Tabilo won the title after defeating Jesper de Jong 6–1, 7–5 in the final.

## Seeds

* Jaume Munar (first round)
* Facundo Bagnis (quarterfinals)
* Daniel Elahi Galán (quarterfinals)
* Sebastián Báez (first round)
* Francisco Cerúndolo (second round)
* Thiago Seyboth Wild (semifinals)
* Hugo Dellien (second round)
* Tomás Martín Etcheverry (semifinals)

## 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 | Semifinals | Final | Final | Final |
| | Alejandro Tabilo | 6 | 7$^7$ | | | |
| 6 | Thiago Seyboth Wild | 2 | 6$^2$ | | | |
| 6 | Thiago Seyboth Wild | 2 | 6$^2$ | Alejandro Tabilo | 6 | 7 |
| | | | | Jesper de Jong | 1 | 5 |
| | Jesper de Jong | 7 | 6 | Jesper de Jong | 1 | 5 |
| 8 | Tomás Martín Etcheverry | 5 | 3 | | | |

### Top half

| First round | First round | First round | First round | First round | Second round | Second round | Second round | Second round | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Semifinals | Semifinals | Semifinals | Semifinals |
| 1 | J Munar | 4 | 2 | | | | | | | | | | | | | |
| | A Tabilo | 6 | 6 | | | A Tabilo | 6 | 6 | | | | | | | | |
| WC | Á Guillén Meza | 6 | 3 | 4 | | D King | 3 | 1 | | | | | | | | |
| | D King | 0 | 6 | 6 | | | | | | A Tabilo | 6 | 6 | | | | |
| | G Oliveira | 6 | 7$^7$ | | | | | | | G Oliveira | 4 | 3 | | | | |
| | R Cid Subervi | 3 | 6$^1$ | | | G Oliveira | 6 | 6 | | | | | | | | |
| | V Kopřiva | 7 | 2 | 3 | 5 | F Cerúndolo | 4 | 3 | | | | | | | | |
| 5 | F Cerúndolo | 5 | 6 | 6 | | | | | | | | | | A Tabilo | 6 | 7$^7$ |
| 4 | S Báez | 6$^3$ | 6 | 5 | | | | | | | | | 6 | T Seyboth Wild | 2 | 6$^2$ |
| | N Kicker | 7$^7$ | 4 | 7 | | N Kicker | 7$^7$ | 6 | | | | | | | | |
| Q | D Dutra da Silva | 2 | 7$^7$ | 6 | Q | D Dutra da Silva | 6$^5$ | 3 | | | | | | | | |
| | N Hardt | 6 | 6$^5$ | 0 | | | | | | N Kicker | 4 | 6$^8$ | | | | |
| Q | A González | 6 | 6 | | | | | | 6 | T Seyboth Wild | 6 | 7$^{10}$ | | | | |
| Alt | A Galarneau | 2 | 4 | | Q | A González | 6$^2$ | 0 | | | | | | | | |
| | A Collarini | 3 | 7$^7$ | 2 | 6 | T Seyboth Wild | 7$^7$ | 6 | | | | | | | | |
| 6 | T Seyboth Wild | 6 | 6$^3$ | 6 | | | | | | | | | | | | |

### 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 | Quarterfinals | Semifinals | Semifinals | Semifinals | Semifinals |
| 7 | H Dellien | 6 | 6 | | | | | | | | | | | | | | | |
| | P Krstin | 4 | 2 | | 7 | H Dellien | 1 | 0 | | | | | | | | | | |
| | J de Jong | 3 | 7$^7$ | 0 | | J de Jong | 6 | 6 | | | | | | | | | | |
| | G Andreozzi | 6 | 6$^4$ | 0$^r$ | | | | | | | J de Jong | 6 | 6$^5$ | 6 | | | | |
| Q | Facundo Juárez | 3 | 6 | 6 | | | | | | 3 | DE Galán | 2 | 7$^7$ | 3 | | | | |
| Alt | F Díaz Acosta | 6 | 4 | 4 | Q | F Juárez | 4 | 3 | | | | | | | | | | |
| | N Mejía | 2 | 5 | | 3 | DE Galán | 6 | 6 | | | | | | | | | | |
| 3 | DE Galán | 6 | 7 | | | | | | | | | | | | | J de Jong | 7 | 6 |
| 8 | TM Etcheverry | 6 | 3 | 7 | | | | | | | | | | | 8 | TM Etcheverry | 5 | 3 |
| | R Quiroz | 1 | 6 | 5 | 8 | TM Etcheverry | 6 | 3 | 7$^7$ | | | | | | | | | |
| LL | N Álvarez Varona | 2 | 6 | 6 | LL | N Álvarez Varona | 4 | 6 | 6$^4$ | | | | | | | | | |
| WC | D Hidalgo | 6 | 4 | 3 | | | | | | 8 | TM Etcheverry | 6 | 6 | | | | | |
| Q | N Álvarez | 4 | 7 | 6 | | | | | | 2/WC | F Bagnis | 4 | 0 | | | | | |
| | TA Tirante | 6 | 5 | 3 | Q | N Álvarez | 2 | 6 | 1 | | | | | | | | | |
| | H Casanova | 2 | 2 | | 2/WC | F Bagnis | 6 | 4 | 6 | | | | | | | | | |
| 2/WC | F Bagnis | 6 | 6 | | | | | | | | | | | | | | | |