Singles
2021 Generali Open Kitzbühel
Final
Champion	Casper Ruud
Runner-up	Pedro Martínez
Score	6–1, 4–6, 6–3
Details
Draw	28
Seeds	8
Events
Singles Doubles
← 2020 · Generali Open Kitzbühel · 2022 →

Miomir Kecmanović was the defending champion, but chose to compete at the Summer Olympics instead.

Casper Ruud won his fifth ATP Tour title, defeating Pedro Martínez in the final, 6–1, 4–6, 6–3. It was Ruud's third consecutive title in as many weeks.

The top four seeds receive a bye into the second round.

	Semifinals							Final
	1	Casper Ruud	6	79
	Alt	Arthur Rinderknech	3	67
								1	Casper Ruud	6	4	6
									Pedro Martínez	1	6	3
	SE	Daniel Altmaier	6	3	3
		Pedro Martínez	4	6	6

	First round							Second round							Quarterfinals							Semifinals
								1	C Ruud	7	5	6
	LL	M Vilella Martínez	64	7	6			LL	M Vilella Martínez	5	7	4
	Q	L Neumayer	77	5	4										1	C Ruud	3	77	6
		P Cuevas	3	5												M Ymer	6	65	1
		M Ymer	6	7					M Ymer	6	6
	WC	A Erler	7	1	6			WC	A Erler	2	3
	10	C Alcaraz	5	6	2																	1	C Ruud	6	79
																						Alt	A Rinderknech	3	67
								3	F Krajinović	6	2	6
	WC	T Seyboth Wild	6	3	2			LL	C Taberner	3	6	4
	LL	C Taberner	3	6	6										3	F Krajinović	4	1
		S Travaglia	3	4											Alt	A Rinderknech	6	6
	Q	H Rune	6	6				Q	H Rune	4	6	64
	Alt	A Rinderknech	6	6				Alt	A Rinderknech	6	3	77
	5	F Delbonis	2	4

	First round							Second round							Quarterfinals							Semifinals
	6	L Đere	6	3	3
	SE	D Altmaier	4	6	6			SE	D Altmaier	6	6
		R Albot	3	67					M Cecchinato	4	4
		M Cecchinato	6	79											SE	D Altmaier	6	65	6
		G Mager	6	6												G Mager	1	77	3
	WC	D Novak	4	0					G Mager	77	1	7
								4	A Ramos Viñolas	63	6	5
																						SE	D Altmaier	6	3	3
	9	J Munar	4	4																			P Martínez	4	6	6
	Q	J Kovalík	6	6				Q	J Kovalík	2	6	6
		J Veselý	6	6					J Veselý	6	2	4
	Q	E Gulbis	4	1											Q	J Kovalík	2	2
		L Pouille	3	77	4											P Martínez	6	6
		P Martínez	6	64	6				P Martínez	6	65	7
								2	R Bautista Agut	4	77	5

	First round							Qualifying competition
	1	Carlos Taberner	6	77
		Evgeny Karlovskiy	4	64
								1	Carlos Taberner	3	6	3
									Ernests Gulbis	6	3	6
		Ernests Gulbis	6	6
	7	Nikola Milojević	3	4

	First round							Qualifying competition
	2	Andrej Martin	6	6
		Zizou Bergs	4	3
								2	Andrej Martin	5	5
									Holger Rune	7	7
		Holger Rune	78	6
	6	Marc Polmans	66	3

	First round							Qualifying competition
	3	Jozef Kovalík	6	6
	WC	Leandro Riedi	2	4
								3	Jozef Kovalík	7	7
								8	Mario Vilella Martínez	5	5
	Alt	Lucas Miedler	3	4
	8	Mario Vilella Martínez	6	6

	First round							Qualifying competition
	4	Juan Ignacio Londero	67	0r
	WC	Lukas Neumayer	79	0
								WC	Lukas Neumayer	6	77
									Lukáš Rosol	4	65
		Lukáš Rosol	6	610	6
	5	Juan Manuel Cerúndolo	3	712	1

• Main draw
• Qualifying draw