2021 Challenger Ciudad de Guayaquil

Country	Player	Rank1	Seed
ESP	Jaume Munar	75	1
ARG	Facundo Bagnis	81	2
COL	Daniel Elahi Galán	106	3
ARG	Sebastián Báez	112	4
ARG	Francisco Cerúndolo	113	5
BRA	Thiago Seyboth Wild	126	6
BOL	Hugo Dellien	128	7
ARG	Tomás Martín Etcheverry	133	8

• ¹ Rankings are as of 25 October 2021.^[1]

The following players received wildcards into the singles main draw:

• Facundo Bagnis
• Álvaro Guillén Meza
• Diego Hidalgo

The following players received entry into the singles main draw as alternates:

• Facundo Díaz Acosta
• Alexis Galarneau

The following players received entry from the qualifying draw:

• Nicolás Álvarez
• Daniel Dutra da Silva
• Alejandro González
• Facundo Juárez

The following player received entry as a lucky loser:

• Nicolás Álvarez Varona

• Alejandro Tabilo def. Jesper de Jong 6–1, 7–5.

• Jesper de Jong / Bart Stevens def. Diego Hidalgo / Cristian Rodríguez 7–5, 6–2.