Singles
2021 Open de Oeiras II
Champion	Pedro Cachin
Runner-up	Nuno Borges
Score	7–6(7–4), 7–6(7–3)

This was the second of four editions of the tournament in the 2021 ATP Challenger Tour calendar.^[1]

Zdeněk Kolář was the defending champion but chose not to defend his title.

Pedro Cachin won the title after defeating Nuno Borges 7–6^(7–4), 7–6^(7–3) in the final.

Seeds

Draw

Finals

	Semifinals							Final
		Gonçalo Oliveira	64	0r
	Q	Pedro Cachin	77	4
								Q	Pedro Cachin	77	77
								WC	Nuno Borges	64	63
	SE	Gastão Elias	6	2	3
	WC	Nuno Borges	4	6	6

Top half

	First round							Second round							Quarterfinals							Semifinals
	1	O Otte	6	6
	WC	Pedro Araújo	2	4				1	O Otte	4	6	3
		R Bonadio	64	5					G Oliveira	6	4	6
		G Oliveira	77	7												G Oliveira	7	6
		M Zverev	4												WC	T Cação	5	2
		M Moraing	3r						M Zverev	3	6	66
	WC	T Cação	6	6				WC	T Cação	6	1	78
	8	T Lamasine	2	4																			G Oliveira	64	0r
	4	E Benchetrit	2	1																		Q	P Cachin	77	4
	Q	P Cachin	6	6				Q	P Cachin	6	6
		C-h Tseng	6	65	3			Q	A Andreev	2	4
	Q	A Andreev	1	77	6										Q	P Cachin	6	2	6
		P Kotov	6	3											5	GM Moroni	3	6	4
	Alt	H Bourchier	0	0r					P Kotov	2	2
		A Molčan	2	4				5	GM Moroni	6	6
	5	GM Moroni	6	6

Bottom half

	First round							Second round							Quarterfinals							Semifinals
	6	M Trungelliti	1	4
	SE	G Elias	6	6				SE	G Elias	6	6
		C Gimeno Valero	6	6					C Gimeno Valero	1	3
		R Ortega Olmedo	1	1											SE	G Elias	w/o
		D Kuzmanov	6	6												D Kuzmanov
		L Miedler	1	0					D Kuzmanov	6	6
	Q	E Furness	3	2				3	E Escobedo	2	2
	3	E Escobedo	6	6																		SE	G Elias	6	2	3
	7	N Kuhn	1	4																		WC	N Borges	4	6	6
		M Guinard	6	6					M Guinard	6	6
		H Grenier	6	6					H Grenier	4	1
		D-h Lee	0	3												M Guinard	3	6	3
	Alt	J Forejtek	3r												WC	N Borges	6	3	6
	Q	R Brancaccio	4					Q	R Brancaccio	4	6	3
	WC	N Borges	6	6				WC	N Borges	6	4	6
	2	E Couacaud	3	4

References

External links

• Main draw
• Qualifying draw