Liudmila Samsonova defeated Belinda Bencic in the final, 1–6, 6–1, 6–3, to win the singles tennis title at the 2021 WTA German Open. Samsonova was contesting her first career final on the WTA Tour and had entered the main draw as a qualifier. Her win made her the 10th maiden titlist on the 2021 WTA Tour and the second qualifier of the season to claim a title.^[1]

Dinara Safina was the defending champion from when the event was last held in 2008 on clay courts,^[2] but she retired from professional tennis in 2014.^[3] As the inaugural edition of the tournament following its relaunch, this marked the first year the tournament was played on grass.

	Semifinals							Final
	Q	Liudmila Samsonova	6	6
	7	Victoria Azarenka	4	2
								Q	Liudmila Samsonova	1	6	6
								5	Belinda Bencic	6	1	3
		Alizé Cornet	5	4
	5	Belinda Bencic	7	6

	First round							Second round							Quarterfinals							Semifinals
								1	A Sabalenka	4	6	5
	Q	M Fręch	3	4					M Keys	6	1	7
		M Keys	6	6												M Keys	64	6	60
		M Vondroušová	4	66											Q	L Samsonova	77	2	77
	Q	L Samsonova	6	78				Q	L Samsonova	6	6
		V Kudermetova	77	5	6				V Kudermetova	4	3
	8	K Muchová	65	7	2																	Q	L Samsonova	6	6
																						7	V Azarenka	4	2
								4	Ka Plíšková	5	2
		J Pegula	6						J Pegula	7	6
	Q	H Baptiste	6r													J Pegula	2	7	4
		A Kerber	6	6											7	V Azarenka	6	5	6
	Q	M Doi	2	1					A Kerber	3	5
	WC	A Petkovic	4	62				7	V Azarenka	6	7
	7	V Azarenka	6	77

	First round							Second round							Quarterfinals							Semifinals
	6	G Muguruza	6	6
		S Cîrstea	3	2				6	G Muguruza	6	6
		E Rybakina	2	6	6				E Rybakina	4	3
		S Rogers	6	3	4										6	G Muguruza	6	3	65
		A Anisimova	3	1												A Cornet	4	6	77
		A Cornet	6	6					A Cornet	77	7
								3	B Andreescu	62	5
																							A Cornet	5	4
	5	B Bencic	4	6	7																	5	B Bencic	7	6
	Q	J Niemeier	6	4	5			5	B Bencic	6	6
		P Martić	77	4	6				P Martić	3	4
	Q	A Muhammad	60	6	3										5	B Bencic	6	4	77
		E Alexandrova	6	6												E Alexandrova	4	6	64
	WC	A Kalinskaya	3	2					E Alexandrova	6	7
								2	E Svitolina	4	5

	First round							Qualifying competition
	1	Ann Li	3	62
	WC	Jule Niemeier	6	77
								WC	Jule Niemeier	77	6
								8	Claire Liu	63	1
		Varvara Flink	2	3
	8	Claire Liu	6	6

	First round							Qualifying competition
	2	Anna Blinkova	5	2
	PR	Mandy Minella	7	6
								PR	Mandy Minella	2	3
									Magdalena Fręch	6	6
		Magdalena Fręch	3	6	6
	11	Tamara Korpatsch	6	1	0

	First round							Qualifying competition
	3	Misaki Doi	77	7
		Mona Barthel	62	5
								3	Misaki Doi	6	64	77
								7	Anna-Lena Friedsam	3	77	63
		Varvara Lepchenko	3	4r
	7	Anna-Lena Friedsam	6	3

	First round							Qualifying competition
	4	Kaja Juvan	3	7	5
		Asia Muhammad	6	5	7
									Asia Muhammad	7	5	6
								9	Stefanie Vögele	5	7	3
	WC	Julia Middendorf	1	2
	9	Stefanie Vögele	6	6

	First round							Qualifying competition
	5	Aliaksandra Sasnovich	3	64
		Priscilla Hon	6	77
									Priscilla Hon	3	5
									Hailey Baptiste	6	7
		Hailey Baptiste	6	6
	12	Jaqueline Cristian	3	1

	First round							Qualifying competition
	6	Liudmila Samsonova	6	6
	WC	Noma Noha Akugue	3	1
								6	Liudmila Samsonova	4	6	77
								10	Ana Konjuh	6	1	64
	WC	Nicole Rivkin	4	0
	10	Ana Konjuh	6	6

• Official website
• WTA website
• Main draw
• Qualifying draw