Men's singles
2021 I.ČLTK Prague Open
Final
Champion	Tallon Griekspoor
Runner-up	Oscar Otte
Score	5–7, 6–4, 6–4
Events
Singles men women Doubles men women
← 2020 · I.ČLTK Prague Open · 2022 →

The men's singles of the 2021 I.ČLTK Prague Open tournament was played on clay in Prague, Czech Republic.

Stan Wawrinka was the defending champion^[1] but chose not to partake in this edition.

Tallon Griekspoor won the title after defeating Oscar Otte 5–7, 6–4, 6–4 in the final.

	Semifinals							Final
	1	Norbert Gombos	65	3
		Tallon Griekspoor	77	6
									Tallon Griekspoor	5	6	6
									Oscar Otte	7	4	4
	WC	Michael Vrbenský	3	3
		Oscar Otte	6	6

	First round							Second round							Quarterfinals							Semifinals
	1	N Gombos	66	6	6
		H Laaksonen	78	4	3			1	N Gombos	6	61	6
	Q	K Żuk	77	2	7			Q	K Żuk	3	77	3
		M Vilella Martínez	65	6	5										1	N Gombos	6	6
		D Popko	3	4											8	S Nagal	4	2
	Q	S Stakhovsky	6	6				Q	S Stakhovsky	6	1	4
	Q	Z Kolář	2	4				8	S Nagal	4	6	6
	8	S Nagal	6	6																		1	N Gombos	65	3
	4	D Novak	4	61																			T Griekspoor	77	6
	SE	R Olivo	6	77				SE	R Olivo	3	63
		L Rosol	3	0					T Griekspoor	6	77
		T Griekspoor	6	6												T Griekspoor	6	6
		R Marcora	64	2												F Ferreira Silva	2	4
		M Polmans	77	6					M Polmans	2	6	4
		F Ferreira Silva	6	65	6				F Ferreira Silva	6	3	6
	6	K Majchrzak	4	77	1

	First round							Second round							Quarterfinals							Semifinals
	5	D Kudla	1	4
		Y Maden	6	6					Y Maden	6	4	1
	Q	V Kopřiva	6	64	78			Q	V Kopřiva	4	6	6
		I Marchenko	2	77	66										Q	V Kopřiva	1	4
	WC	M Vrbenský	77	6											WC	M Vrbenský	6	6
		S Ofner	64	3				WC	M Vrbenský	6	1	6
	WC	A Paulson	3	3				3	A Martin	4	6	4
	3	A Martin	6	6																		WC	M Vrbenský	3	3
	7	P Gojowczyk	3	1																			O Otte	6	6
		O Otte	6	6					O Otte	6	3	6
	WC	J Lehečka	4	6	77			WC	J Lehečka	1	6	3
		R Safiullin	6	3	64											O Otte	6	7
		M Cressy	6	6												M Cressy	3	5
		M Safwat	2	2					M Cressy	6	7
		A Tabilo	7	4					A Tabilo	2	5
	2	Y Sugita	5	0r

• Main draw
• Qualifying draw