2021 MercedesCup – Singles

Singles
2021 MercedesCup
Champion	Marin Čilić
Runner-up	Félix Auger-Aliassime
Final score	7–6(7–2), 6–3

Main article: 2021 MercedesCup

Marin Čilić defeated Félix Auger-Aliassime in the final, 7–6^(7–2), 6–3, to win the singles tennis title at the 2021 Stuttgart Open. It was Čilić's 19th career ATP Tour singles title, his first in three years, and he did not drop a set en route to the victory. The No. 47-ranked 32-year-old Čilić also became the lowest-ranked winner since Juan Carlos Ferrero in 2011 and the third-oldest champion in tournament history. 2019 finalist Auger-Aliassime was contesting for his first career singles title in his eighth final.

Matteo Berrettini was the defending champion from when the event was last held in 2019, but he could not participate as he was still competing at the 2021 French Open upon the beginning of the tournament.

Seeds

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

1. Denis Shapovalov (quarterfinals)
2. Hubert Hurkacz (second round)
3. Félix Auger-Aliassime (final)
4. Alex de Minaur (quarterfinals)
5. Nikoloz Basilashvili (second round)
6. Ugo Humbert (quarterfinals)
7. Adrian Mannarino (first round)
8. John Millman (withdrew)

Draw

Key

• Q = Qualifier
• WC = Wild Card
• LL = Lucky Loser

• Alt = Alternate
• SE = Special Exempt
• PR = Protected Ranking

• w/o = Walkover
• r = Retired
• d = Defaulted

Finals

	Semifinals							Final
		Marin Čilić	6	1
	WC	Jurij Rodionov	3	0r
									Marin Čilić	77	6
								3	Félix Auger-Aliassime	62	3
	3	Félix Auger-Aliassime	6	7
		Sam Querrey	4	5

Top half

	First round							Second round							Quarterfinals							Semifinals
								1	D Shapovalov	6	62	6
		F López	6	6					F López	2	77	3
		A Popyrin	4	4											1	D Shapovalov	5	63
		M Čilić	7	6												M Čilić	7	77
	WC	R Molleker	5	3					M Čilić	6	6
	WC	D Brown	3	64				5	N Basilashvili	3	2
	5	N Basilashvili	6	77																			M Čilić	6	1
																						WC	J Rodionov	3	0r
								4	A de Minaur	68	6	6
		G Pella	3	4					J Thompson	710	3	4
		J Thompson	6	6											4	A de Minaur	6	3	64
		D Koepfer	6	3	2										WC	J Rodionov	3	6	77
	WC	J Rodionov	2	6	6			WC	J Rodionov	5
	Q	P Gojowczyk	5	6	6			Q	P Gojowczyk	3r
	LL	I Ivashka	7	4	2

Bottom half

	First round							Second round							Quarterfinals							Semifinals
	6	U Humbert	6	6
		M Fucsovics	3	1				6	U Humbert	711	6
		J Chardy	4	4				WC	Y Hanfmann	69	2
	WC	Y Hanfmann	6	6											6	U Humbert	65	68
		G Simon	4	5											3	F Auger-Aliassime	77	710
		L Harris	6	7					L Harris	3	64
								3	F Auger-Aliassime	6	77
																						3	F Auger-Aliassime	6	7
	7	A Mannarino	3	2																			S Querrey	4	5
	Q	J Duckworth	6	6				Q	J Duckworth	4	67
	Q	A Çelikbilek	4	1					S Querrey	6	79
		S Querrey	6	6												S Querrey	64	77	6
	Q	R Albot	64	65											WC	DS Stricker	77	64	3
	WC	DS Stricker	77	77				WC	DS Stricker	77	77
								2	H Hurkacz	65	65

Qualifying

Seeds

1. Sam Querrey (moved to main draw)
2. Gilles Simon (moved to main draw)
3. Jiří Veselý (first round)
4. Emil Ruusuvuori (qualifying competition)
5. Marcos Giron (first round)
6. Lucas Pouille (first round)
7. Radu Albot (qualified)
8. Ilya Ivashka (qualifying competition, lucky loser)

Qualifiers

1. James Duckworth
2. Peter Gojowczyk
3. Altuğ Çelikbilek
4. Radu Albot

Lucky loser

1. Ilya Ivashka

Draw

First qualifier

	First round							Qualifying competition
	Alt	Luke Saville	78	4	4
	Alt	James Duckworth	66	6	6
								Alt	James Duckworth	77	3	7
								8	Ilya Ivashka	65	6	5
	WC	Daniel Masur	0	64
	8	Ilya Ivashka	6	77

Second qualifier

	First round							Qualifying competition
	Alt	Sergiy Stakhovsky	1	64
	Alt	Peter Gojowczyk	6	77
								Alt	Peter Gojowczyk	6	6
								Alt	Grégoire Barrère	2	4
	Alt	Grégoire Barrère	6	6
	5	Marcos Giron	3	2

Third qualifier

	First round							Qualifying competition
	3	Jiří Veselý	77	2	4
	Alt	Dennis Novak	65	6	6
								Alt	Dennis Novak	6	63	5
								Alt	Altuğ Çelikbilek	1	77	7
	Alt	Altuğ Çelikbilek	6	2	6
	6	Lucas Pouille	3	6	3

Fourth qualifier

	First round							Qualifying competition
	4	Emil Ruusuvuori	7	6
	Alt	João Sousa	5	3
								4	Emil Ruusuvuori	65	4
								7	Radu Albot	77	6
	Alt	Christopher O'Connell	3	0r
	7	Radu Albot	6	0

External links

• Main draw
• Qualifying draw