2021 Ambato La Gran Ciudad

Country	Player	Rank1	Seed
PER	Juan Pablo Varillas	122	1
SVK	Andrej Martin	123	2
BOL	Hugo Dellien	144	3
ECU	Emilio Gómez	156	4
ARG	Renzo Olivo	207	5
ARG	Juan Pablo Ficovich	247	6
ARG	Thiago Agustín Tirante	267	7
BIH	Mirza Bašić	269	8

• ¹ Rankings are as of 13 September 2021.^[1]

The following players received wildcards into the singles main draw:

• Daniel Espín Pérez
• Diego Hidalgo
• Antonio Cayetano March

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

• Gerald Melzer

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

• Gonzalo Lama

The following players received entry from the qualifying draw:

• Alejandro Gómez
• Patrick Kypson
• Pol Martín Tiffon
• Matías Zukas

The following players received entry as lucky losers:

• Alexis Gautier
• Alejandro González

• Thiago Agustín Tirante def. Juan Pablo Varillas 7–5, 7–5.

• Diego Hidalgo / Cristian Rodríguez def. Alejandro Gómez / Thiago Agustín Tirante 6–3, 4–6, [10–3].