Singles
2021 Slovak Open II
Champion	Tallon Griekspoor
Runner-up	Zsombor Piros
Score	6–3, 6–2

Maximilian Marterer was the defending champion^[1] but lost in the quarterfinals to Stefano Travaglia.

Tallon Griekspoor won the title after defeating Zsombor Piros 6–3, 6–2 in the final.

Seeds

Draw

Finals

	Semifinals							Final
	1	Stefano Travaglia	65	2r
	Q	Zsombor Piros	77	3
								Q	Zsombor Piros	3	2
								2	Tallon Griekspoor	6	6
	5	Alex Molčan	77	3	4
	2	Tallon Griekspoor	65	6	6

Top half

	First round							Second round							Quarterfinals							Semifinals
	1	S Travaglia	77	6
		Z Kolář	64	3				1	S Travaglia	6	6
		C İlkel	6	61	6				C İlkel	4	2
	LL	A Shevchenko	4	77	3										1	S Travaglia	77	6
		M Marterer	4	6	6											M Marterer	61	1
		J Rodionov	6	1	4				M Marterer	6	78
		I Marchenko	2	1				7	L Broady	4	66
	7	L Broady	6	6																		1	S Travaglia	65	2r
	3	C Taberner	2	65																		Q	Z Piros	77	3
		F Ferreira Silva	6	77					F Ferreira Silva	6	7
	Q	D Svrčina	2	77	6			Q	D Svrčina	4	5
		F Horanský	6	65	1											F Ferreira Silva	0	4
	Q	Miloš Karol	4	3											Q	Z Piros	6	6
		L Lacko	6	6					L Lacko	2	4
	Q	Z Piros	7	3	6			Q	Z Piros	6	6
	8	T Macháč	5	6	4

Bottom half

	First round							Second round							Quarterfinals							Semifinals
	5	A Molčan	6	79
		R Ramanathan	3	67				5	A Molčan	6	6
	WC	J Forejtek	2	4				Alt	T Kamke	2	2
	Alt	T Kamke	6	6											5	A Molčan	6	4	6
		J Sousa	66	77	62											D Džumhur	1	6	3
		A Çelikbilek	78	63	77				A Çelikbilek	4	4
		D Džumhur	6	6					D Džumhur	6	6
	4	N Gombos	3	3																		5	A Molčan	77	3	4
	LL	S Mochizuki	65	3																		2	T Griekspoor	65	6	6
		K Żuk	77	6					K Żuk	6	3	2
		S Stakhovsky	4	5					J Lehečka	2	6	6
		J Lehečka	6	7												J Lehečka	63	4
	Q	D Kalenichenko	77	77											2	T Griekspoor	77	6
	WC	Lukáš Palovič	64	65				Q	D Kalenichenko	62	61
	WC	Lukáš Pokorný	64	1				2	T Griekspoor	77	77
	2	T Griekspoor	77	6

References

• Main draw
• Qualifying draw