Singles
2021 St. Petersburg Ladies' Trophy
Final
Champion	Daria Kasatkina
Runner-up	Margarita Gasparyan
Score	6–3, 2–1, ret.
Details
Draw	28 (6 Q / 4 WC )
Seeds	8
Events
Singles Doubles
← 2020 · St. Petersburg Ladies' Trophy · 2022 →

Daria Kasatkina won the women's singles title at the 2021 St. Petersburg Ladies' Trophy, after Margarita Gasparyan retired from the final with the scoreline at 6–3, 2–1.

Kiki Bertens was the two-time defending champion,^[1] but she chose not to participate.

This was the first tournament since Oakland in 1993 in which seven of the eight quarterfinalists were all from the same country. It was also the first tournament in WTA history in which all four semifinalists represented Russia.^[2][3]

	Semifinals							Final
	WC	Margarita Gasparyan	6	711
	WC	Vera Zvonareva	3	69
								WC	Margarita Gasparyan	3	1r
								8	Daria Kasatkina	6	2
	4	Svetlana Kuznetsova	6	0	2
	8	Daria Kasatkina	1	6	6

	First round							Second round							Quarterfinals							Semifinals
								1	E Alexandrova	6	6
		S Vögele	0	6	4				T Martincová	3	4
		T Martincová	6	4	6										1	E Alexandrova	2	5
		K Siniaková	6	6											WC	M Gasparyan	6	7
		K Flipkens	1	2					K Siniaková	4	4
	WC	M Gasparyan	61	6	6			WC	M Gasparyan	6	6
	7	K Mladenovic	77	1	1																	WC	M Gasparyan	6	711
																						WC	V Zvonareva	3	69
								3	F Ferro	78	5	62
	Q	Ar Rodionova	1	3				WC	V Zvonareva	66	7	77
	WC	V Zvonareva	6	6											WC	V Zvonareva	6	6
		K Zavatska	2	78	5										Q	A Gasanova	3	1
	Q	A Gasanova	6	66	7			Q	A Gasanova	1	710	77
	LL	Ç Büyükakçay	4	4				5	A Pavlyuchenkova	6	68	64
	5	A Pavlyuchenkova	6	6

	First round							Second round							Quarterfinals							Semifinals
	6	J Ostapenko	6	6
		P Badosa	2	2				6	J Ostapenko	3	69
	Q	J Cristian	63	6	2			Q	J Cristian	6	711
	PR	V Lapko	77	4	1r										Q	J Cristian	77	3	3
	Q	Xin Wang	6	5	7										4	S Kuznetsova	65	6	6
		V Tomova	1	7	5			Q	Xin Wang	1	5
								4	S Kuznetsova	6	7
																						4	S Kuznetsova	6	0	2
	8	D Kasatkina	6	77																		8	D Kasatkina	1	6	6
	Q	C Tauson	4	60				8	D Kasatkina	5	6	77
		A Bogdan	6	2	1				A Sasnovich	7	3	62
		A Sasnovich	2	6	6										8	D Kasatkina	1	6	6
	WC	D Mishina	1	77	1										2	V Kudermetova	6	1	2
	Q	K Rakhimova	6	62	6			Q	K Rakhimova	5	6	65
								2	V Kudermetova	7	3	77

	First round							Qualifying competition
	1	Clara Tauson	7	6
	WC	Ekaterina Shalimova	5	3
								1	Clara Tauson	7	6
								11	Lesley Pattinama Kerkhove	5	2
		Ekaterine Gorgodze	6	60	3
	11	Lesley Pattinama Kerkhove	0	77	6

	First round							Qualifying competition
	Alt	Sofya Lansere	3	0
	WC	Alina Charaeva	6	6
								WC	Alina Charaeva	6	1	2
								7	Jaqueline Cristian	4	6	6
		Natalija Kostić	1	3
	7	Jaqueline Cristian	6	6

	First round							Qualifying competition
	3	Monica Niculescu	3	4
	WC	Ana Konjuh	6	6
								WC	Ana Konjuh	4	3
									Anastasia Gasanova	6	6
		Anastasia Gasanova	6	6
	12	Laura Ioana Paar	4	3

	First round							Qualifying competition
	4	Natalia Vikhlyantseva	6	4	1
		Valeria Savinykh	2	6	6
									Valeria Savinykh	3	4
								9	Arina Rodionova	6	6
		Kathinka von Deichmann	4	4
	9	Arina Rodionova	6	6

	First round							Qualifying competition
	5	Kamilla Rakhimova	6	4	6
		Aleksandra Krunić	2	6	4
								5	Kamilla Rakhimova	6	2	6
								8	Magdalena Fręch	3	6	2
	WC	Polina Kudermetova	1	3
	8	Magdalena Fręch	6	6

	First round							Qualifying competition
	6	Wang Xinyu	6	6
		Marina Melnikova	2	3
								6	Wang Xinyu	6	6
								10	Çağla Büyükakçay	2	3
		Jana Fett	3	6	5
	10	Çağla Büyükakçay	6	4	7

• Main draw
• Qualifying draw