2021 Open de Oeiras II

Country	Player	Rank1	Seed
GER	Oscar Otte	154	1
FRA	Enzo Couacaud	185	2
USA	Ernesto Escobedo	205	3
MAR	Elliot Benchetrit	240	4
ITA	Gian Marco Moroni	241	5
ARG	Marco Trungelliti	247	6
ESP	Nicola Kuhn	250	7
FRA	Tristan Lamasine	257	8

• ¹ Rankings are as of 22 March 2021.^[1]

The following players received wildcards into the singles main draw:

• Pedro Araújo
• Nuno Borges
• Tiago Cação

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

• Gastão Elias

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

• Harry Bourchier
• Jonáš Forejtek

The following players received entry from the qualifying draw:

• Adrian Andreev
• Raúl Brancaccio
• Pedro Cachin
• Evan Furness

• Pedro Cachin def. Nuno Borges 7–6^(7–4), 7–6^(7–3).

• Nuno Borges / Francisco Cabral def. Pavel Kotov / Tseng Chun-hsin 6–1, 6–2.