2021 Astana Open – Men's singles

John Millman was the defending champion,^[1] but lost in the quarterfinals to James Duckworth.

Men's singles
2021 Astana Open
Champion	Kwon Soon-woo
Runner-up	James Duckworth
Score	7–6(8–6), 6–3

Main article: 2021 Astana Open

Kwon Soon-woo won his first ATP Tour title, defeating Duckworth in the final, 7–6^(8–6), 6–3. Kwon became the first South Korean player to win a title at ATP Tour level since Lee Hyung-taik in the 2003 Sydney tournament.

Seeds

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

1. Aslan Karatsev (second round)
2. Alexander Bublik (semifinals)
3. Dušan Lajović (second round)
4. Filip Krajinović (second round)
5. John Millman (quarterfinals)
6. Benoît Paire (first round)
7. Laslo Đere (quarterfinals)
8. Ilya Ivashka (semifinals)

Draw

Key

• Q = Qualifier
• WC = Wild card
• LL = Lucky loser
• Alt = Alternate
• ITF = ITF entry
• PR = Protected ranking
• SR = Special ranking
• SE = Special exempt
• JE = Junior exempt
• JR = Junior Accelerator Programme entrant
• CO = College Accelerator Programme entrant
• NG = Next Gen Accelerator Program entrant
• w/o = Walkover
• r = Retired
• d = Defaulted

Finals

	Semifinals							Final
	8	Ilya Ivashka	3	64
		James Duckworth	6	77
									James Duckworth	66	3
									Kwon Soon-woo	78	6
		Kwon Soon-woo	3	7	6
	2	Alexander Bublik	6	5	3

Top half

	First round							Second round							Quarterfinals							Semifinals
								1	A Karatsev	66	4
		E Ruusuvuori	6	0					E Ruusuvuori	78	6
		B Bonzi	2	0r												E Ruusuvuori	6	4	1
		A Seppi	63	6	1										8	I Ivashka	4	6	6
	WC	T Skatov	77	4	6			WC	T Skatov	2	3
	Q	E Ymer	2	4				8	I Ivashka	6	6
	8	I Ivashka	6	6																		8	I Ivashka	3	64
																							J Duckworth	6	77
								4	F Krajinović	62	3
	WC	M Kukushkin	63	1					J Duckworth	77	6
		J Duckworth	77	6												J Duckworth	6	6
		J Veselý	3	66											5	J Millman	4	4
		J Munar	6	78					J Munar	4	77	5
	Q	D Popko	6	1	4			5	J Millman	6	65	7
	5	J Millman	3	6	6

Bottom half

	First round							Second round							Quarterfinals							Semifinals
	7	L Đere	6	3	6
		DE Galán	4	6	4			7	L Đere	6	63	6
	Q	M Polmans	4	6	4				L Musetti	4	77	4
		L Musetti	6	2	6										7	L Đere	64	6	0
		S-w Kwon	6	6												S-w Kwon	77	2	6
	Q	E Donskoy	4	3					S-w Kwon	7	6
								3	D Lajović	5	4
																							S-w Kwon	3	7	6
	6	B Paire	5	4																		2	A Bublik	6	5	3
		E Gerasimov	7	6					E Gerasimov	7	65	5
		C Taberner	7	6					C Taberner	5	77	7
		R Berankis	5	4												C Taberner	3	4
	WC	F Verdasco	4	2											2	A Bublik	6	6
		M Kecmanović	6	6					M Kecmanović	6	3	5
								2	A Bublik	2	6	7

Qualifying

Seeds

1. Jurij Rodionov (first round)
2. Maxime Cressy (qualifying competition)
3. Marc Polmans (qualified)
4. Evgeny Donskoy (qualified)
5. Illya Marchenko (first round)
6. Kacper Żuk (first round)
7. Elias Ymer (qualified)
8. Dmitry Popko (qualified)

Qualifiers

1. Dmitry Popko
2. Elias Ymer
3. Marc Polmans
4. Evgeny Donskoy

Qualifying draw

First qualifier

	First round							Qualifying competition
	1	Jurij Rodionov	5	4
		Matthew Ebden	7	6
									Matthew Ebden	6	3	4
								8	Dmitry Popko	3	6	6
	WC	Simon Anthony Ivanov	2	3
	8	Dmitry Popko	6	6

Second qualifier

	First round							Qualifying competition
	2	Maxime Cressy	6	2
		Bernard Tomic	3	1r
								2	Maxime Cressy	3	6	4
								7	Elias Ymer	6	4	6
	WC	Grigoriy Lomakin	3	2
	7	Elias Ymer	6	6

Third qualifier

	First round							Qualifying competition
	3	Marc Polmans	2	7	4
		Gian Marco Moroni	6	5	1r
								3	Marc Polmans	6	6
								Alt	Denis Yevseyev	4	2
	Alt	Denis Yevseyev	6	6
	5	Illya Marchenko	4	4

Fourth qualifier

	First round							Qualifying competition
	4	Evgeny Donskoy	77	6
		Andrea Vavassori	64	2
								4	Evgeny Donskoy	6	77
									Pavel Kotov	3	64
		Pavel Kotov	6	6
	6	Kacper Żuk	2	3