Alexander Zverev defeated Matteo Berrettini in the final, 6–7^(8–10), 6–4, 6–3 to win the men's singles tennis title at the 2021 Madrid Open. It was his fourth Masters 1000 title, his first since the 2018 Madrid Open, and his 15th career ATP Tour singles title overall.^[1]

Novak Djokovic was the reigning champion from when the tournament was last held in 2019, but did not participate.^[2]

Following the third-round eliminations of Daniil Medvedev and Stefanos Tsitsipas, respectively, a first-time Masters 1000 singles finalist from the bottom half of the draw was guaranteed; Berrettini went on to become that player.^[3][4]

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

Click on the seed number of a player to go to their draw section.

	Quarterfinals							Semifinals							Final
	1	Rafael Nadal	4	4
	5	Alexander Zverev	6	6
								5	Alexander Zverev	6	6
								3	Dominic Thiem	3	4
	3	Dominic Thiem	3	6	6
		John Isner	6	3	4
															5	Alexander Zverev	68	6	6
															8	Matteo Berrettini	710	4	3
		Alexander Bublik	5	1
		Casper Ruud	7	6
									Casper Ruud	4	4
								8	Matteo Berrettini	6	6
	8	Matteo Berrettini	5	6	6
	16	Cristian Garín	7	3	0

	First round							Second round							Third round							Quarterfinals
								1	R Nadal	6	6
		A Mannarino	4	0				WC	C Alcaraz	1	2
	WC	C Alcaraz	6	6											1	R Nadal	6	6
	Q	A Popyrin	6	77											Q	A Popyrin	3	3
		J-L Struff	3	64				Q	A Popyrin	77	6
		G Pella	2	4r				14	J Sinner	65	2
	14	J Sinner	6	4																		1	R Nadal	4	4
	12	H Hurkacz	7	67	3																	5	A Zverev	6	6
		J Millman	5	79	6				J Millman	77	2	3
		J Chardy	66	79	2				D Evans	65	6	6
		D Evans	78	67	6											D Evans	3	63
		K Khachanov	78	2	2										5	A Zverev	6	77
		K Nishikori	66	6	6				K Nishikori	3	2
								5	A Zverev	6	6

	First round							Second round							Third round							Quarterfinals
								3	D Thiem	6	6
	Q	P Andújar	710	64	5			Q	M Giron	1	3
	Q	M Giron	68	77	7										3	D Thiem	79	6
		A de Minaur	4	7	6											A de Minaur	67	4
	WC	J Munar	6	5	1				A de Minaur	6	3
		L Harris	6	3	77				L Harris	2	0r
	13	G Dimitrov	3	6	65																	3	D Thiem	3	6	6
	9	R Bautista Agut	6	63	7																		J Isner	6	3	4
	Q	M Cecchinato	2	77	5			9	R Bautista Agut	4	77	66
		J Isner	6	78					J Isner	6	64	78
		M Kecmanović	4	66												J Isner	77	3	77
	WC	P Martínez	4	5											6	A Rublev	64	6	64
		T Paul	6	7					T Paul	77	3	4
								6	A Rublev	65	6	6

	First round							Second round							Third round							Quarterfinals
								7	D Schwartzman	6	4	1
		U Humbert	5	4					A Karatsev	2	6	6
		A Karatsev	7	6												A Karatsev	4	3
		M Fucsovics	65	3												A Bublik	6	6
		A Bublik	77	6					A Bublik	6	5	6
		D Lajović	1	3				11	D Shapovalov	4	7	4
	11	D Shapovalov	6	6																			A Bublik	5	1
	15	F Auger-Aliassime	1	4																			C Ruud	7	6
		C Ruud	6	6					C Ruud	6	6
	LL	Y Nishioka	6	6				LL	Y Nishioka	1	2
		F Krajinović	2	4												C Ruud	77	6
		N Basilashvili	4	5											4	S Tsitsipas	64	4
		B Paire	6	7					B Paire	1	2
								4	S Tsitsipas	6	6

	First round							Second round							Third round							Quarterfinals
								8	M Berrettini	6	6
	Q	C Taberner	64	6	3				F Fognini	3	4
		F Fognini	77	2	6										8	M Berrettini	77	6
		T Fritz	5	7	4										Q	F Delbonis	64	4
		A Ramos Viñolas	7	5	6				A Ramos Viñolas	65	3
	Q	F Delbonis	3	6	6			Q	F Delbonis	77	6
	10	P Carreño Busta	6	4	3																	8	M Berrettini	5	6	6
	16	C Garín	6	6																		16	C Garín	7	3	0
	WC	F Verdasco	1	4				16	C Garín	6	6
		D Koepfer	6	6					D Koepfer	3	4
		R Opelka	4	4											16	C Garín	6	62	6
	Q	P-H Herbert	77	64	64										2	D Medvedev	4	77	1
		A Davidovich Fokina	65	77	77				A Davidovich Fokina	6	4	2
								2	D Medvedev	4	6	6

	First round							Qualifying competition
	1	Laslo Đere	3	6	2
		Juan Ignacio Londero	6	3	6
									Juan Ignacio Londero	4	4
								12	Federico Delbonis	6	6
	WC	Bernabé Zapata Miralles	65	65
	12	Federico Delbonis	77	77

	First round							Qualifying competition
	2	Yoshihito Nishioka	6	6
		Pablo Cuevas	4	4
								2	Yoshihito Nishioka	77	4	0r
									Marcos Giron	64	6	0
		Marcos Giron	6	612	77
	11	Thiago Monteiro	4	714	64

	First round							Qualifying competition
	3	Jordan Thompson	6	66	2
	WC	Carlos Taberner	3	78	6
								WC	Carlos Taberner	6	6
									Lorenzo Musetti	4	2
		Lorenzo Musetti	6	6
	14	Radu Albot	3	4

	First round							Qualifying competition
	4	Tennys Sandgren	3	2
		Pierre-Hugues Herbert	6	6
									Pierre-Hugues Herbert	77	6
									Gianluca Mager	64	4
		Gianluca Mager	6	6
	9	Egor Gerasimov	4	3

	First round							Qualifying competition
	5	Frances Tiafoe	64	2
		Marco Cecchinato	77	6
									Marco Cecchinato	4	6	6
									Roberto Carballés Baena	6	0	3
		Roberto Carballés Baena	6	6
	8	Emil Ruusuvuori	2	3

	First round							Qualifying competition
	6	Sebastian Korda	63	4
	WC	Arthur Cazaux	77	6
								WC	Arthur Cazaux	5	60
								10	Alexei Popyrin	7	77
		Federico Coria	77	4	3
	10	Alexei Popyrin	64	6	6

	First round							Qualifying competition
	7	Stefano Travaglia	5	6	7
	WC	Carlos Gimeno Valero	7	1	5
								7	Stefano Travaglia	77	5	3
								13	Pablo Andújar	63	7	6
		Mikhail Kukushkin	3	4
	13	Pablo Andújar	6	6

The following are the seeded players. Seedings are based on ATP rankings as of 26 April 2021. Rankings and points before are as of 3 May 2021.

Seed	Rank	Player	Points before	Points defending	Points won	Points after	Status
1	2	Rafael Nadal	9,810	360	180	9,630	Quarterfinals lost to Alexander Zverev [5]
2	3	Daniil Medvedev	9,700	10	90	9,780	Third round lost to Cristian Garín [16]
3	4	Dominic Thiem	8,365	360	360	8,365	Semifinals lost to Alexander Zverev [5]
4	5	Stefanos Tsitsipas	7,910	390	90	7,610	Third round lost to Casper Ruud
5	6	Alexander Zverev	6,125	180	1,000	6,945	Champion, defeated Matteo Berrettini [8]
6	8	Andrey Rublev	6,000	90	90	6,000	Third round lost to John Isner
7	9	Diego Schwartzman	3,765	67	45	3,743	Second round lost to Aslan Karatsev
8	10	Matteo Berrettini	3,493	45	600	4,048	Runner-up, lost to Alexander Zverev [5]
9	11	Roberto Bautista Agut	3,090	10	45	3,125	Second round lost to John Isner
10	12	Pablo Carreño Busta	3,015	10	10	3,015	First round lost to Federico Delbonis [Q]
11	14	Denis Shapovalov	2,820	10	45	2,855	Second round lost to Alexander Bublik
12	16	Hubert Hurkacz	2,600	67	10	2,543	First round lost to John Millman
13	17	Grigor Dimitrov	2,576	10	10	2,576	First round lost to Lloyd Harris
14	18	Jannik Sinner	2,524	24	45	2,545	Second round lost to Alexei Popyrin [Q]
15	20	Félix Auger-Aliassime	2,418	32	10	2,396	First round lost to Casper Ruud
16	22	Cristian Garín	2,215	45	180	2,350	Quarterfinals lost to Matteo Berrettini [8]

The following players received wildcards into the main draw:

• Carlos Alcaraz
• Pedro Martínez
• Jaume Munar
• Fernando Verdasco

The following players received entry from the qualifying draw:

• Pablo Andújar
• Marco Cecchinato
• Federico Delbonis
• Marcos Giron
• Pierre-Hugues Herbert
• Alexei Popyrin
• Carlos Taberner

The following player received entry as a lucky loser:

• Yoshihito Nishioka

Before the tournament

• Marin Čilić → replaced by Tommy Paul
• Borna Ćorić → replaced by Jérémy Chardy
• Novak Djokovic → replaced by Alejandro Davidovich Fokina
• Roger Federer → replaced by Miomir Kecmanović
• David Goffin → replaced by Lloyd Harris
• Gaël Monfils → replaced by Guido Pella
• Milos Raonic → replaced by Yoshihito Nishioka
• Lorenzo Sonego → replaced by Dominik Koepfer
• Stan Wawrinka → replaced by Albert Ramos Viñolas

• Lloyd Harris
• Guido Pella

• Main draw
• Qualifying draw