Men's singles
2021 Hamburg European Open
Final
Champion	Pablo Carreño Busta
Runner-up	Filip Krajinović
Score	6–2, 6–4
Details
Draw	28 (6Q / 4WC)
Seeds	8
Events
Singles men women Doubles men women
← 2020 · Hamburg European Open · 2022 →

Andrey Rublev was the defending champion,^[1] but chose to not defend his title as he and other Russian Olympic athletes were sent to Yuzhno-Sakhalinsk for training sessions.^[2]

Pablo Carreño Busta won his maiden ATP Tour 500 singles title, defeating Filip Krajinović in the final, 6–2, 6–4.

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

	Semifinals							Final
	6	Filip Krajinović	6	6
		Laslo Đere	4	2
								6	Filip Krajinović	2	4
								2	Pablo Carreño Busta	6	6
		Federico Delbonis	62	3
	2	Pablo Carreño Busta	77	6

	First round							Second round							Quarterfinals							Semifinals
								1/WC	S Tsitsipas	77	6
	Q	M Marterer	62	6	64				D Koepfer	62	3
		D Koepfer	77	2	77										1/WC	S Tsitsipas	6	1	3
		J Munar	65	4											6	F Krajinović	3	6	6
	WC	P Kohlschreiber	77	6				WC	P Kohlschreiber	5	6	3
	WC	D Altmaier	3	77	1			6	F Krajinović	7	4	6
	6	F Krajinović	6	63	6																	6	F Krajinović	6	6
																							L Đere	4	2
								3	N Basilashvili	w/o
		C Moutet	1	2				LL	S Báez
	LL	S Báez	6	6											3	N Basilashvili	2	2
	WC	N Kuhn	6	1	2											L Đere	6	6
	Q	T Seyboth Wild	1	6	6			Q	T Seyboth Wild	61	1
		L Đere	6	7					L Đere	77	6
	7	J-L Struff	4	5

	First round							Second round							Quarterfinals							Semifinals
	8	B Paire	6
		R Berankis	6r					8	B Paire	7	710
	Q	JP Varillas	6	6				Q	JP Varillas	5	68
	LL	S Nagal	0	4											8	B Paire	6	69	4
		F Delbonis	6	5	6											F Delbonis	4	711	6
	Q	Zh Zhang	1	7	4				F Delbonis	6	77
								4	A Ramos Viñolas	3	64
																							F Delbonis	62	3
	5	D Lajović	6	6																		2	P Carreño Busta	77	6
		L Pouille	4	4				5	D Lajović	6	62	6
		G Mager	6	4	63			Q	A Molčan	4	77	3
	Q	A Molčan	4	6	77										5	D Lajović	64	3
	Q	C Taberner	6	3	6										2	P Carreño Busta	77	6
		F López	4	6	3			Q	C Taberner	5	3
								2	P Carreño Busta	7	6

	First round							Qualifying competition
	1	Carlos Taberner	6	6
	WC	Niklas Guttau	1	2
								1	Carlos Taberner	2	77	6
									Daniel Masur	6	65	4
		Daniel Masur	2	6	6
	12	Danilo Petrović	6	4	3

	First round							Qualifying competition
	2	Thiago Seyboth Wild	6	6
	WC	Mats Rosenkranz	3	1
								2	Thiago Seyboth Wild	6	7
									Steven Diez	3	5
		Steven Diez	6	6
	8	Oscar Otte	4	4

	First round							Qualifying competition
	3	Jozef Kovalík	4	4
		Zhang Zhizhen	6	6
									Zhang Zhizhen	6	6
								7	Sumit Nagal	4	2
	WC	Lewie Lane	3	1
	7	Sumit Nagal	6	6

	First round							Qualifying competition
	4	Damir Džumhur	7	2	3
		Maximilian Marterer	5	6	6
									Maximilian Marterer	3	6	7
								11	Alessandro Giannessi	6	3	5
		Tobias Kamke	3	4
	11	Alessandro Giannessi	6	6

	First round							Qualifying competition
	5	Christopher O'Connell	6	6
		Ernests Gulbis	3	0
								5	Christopher O'Connell	3	7	3
								9	Alex Molčan	6	5	6
		Filip Horanský	65	2
	9	Alex Molčan	77	6

	First round							Qualifying competition
	6	Juan Pablo Varillas	7	6
		Jonáš Forejtek	5	2
								6	Juan Pablo Varillas	6	3	77
								10	Sebastián Báez	2	6	60
		Rudolf Molleker	5	2
	10	Sebastián Báez	7	6

• Main draw
• Qualifying draw