Singles
2018 St. Petersburg Open
Final
Champion	Dominic Thiem
Runner-up	Martin Kližan
Score	6–3, 6–1
Details
Draw	28 (4 Q / 3 WC )
Seeds	8
Events
Singles Doubles
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Damir Džumhur was the defending champion, but lost in the quarterfinals to Stan Wawrinka.

Dominic Thiem won the title after defeating Martin Kližan 6–3, 6–1 in the final. Notably, this was Kližan's first defeat in a deciding match, after 10 consecutive titles at ATP World Tour level.

The tournament marked the last appearance of Mikhail Youzhny in professional tennis.^[1]

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

	Semifinals							Final
	1	Dominic Thiem	6	6
	5/WC	Roberto Bautista Agut	4	3
								1	Dominic Thiem	6	6
									Martin Kližan	3	1
	WC	Stan Wawrinka	6	3	5
		Martin Kližan	4	6	7

	First round							Second round							Quarterfinals							Semifinals
								1	D Thiem	77	6
		A Rublev	4	66					J-L Struff	64	4
		J-L Struff	6	78											1	D Thiem	6	3	77
		M Kukushkin	7	2											8	D Medvedev	2	6	62
		D Istomin	5	4r					M Kukushkin	3	4
		J Sousa	4	1				8	D Medvedev	6	6
	8	D Medvedev	6	6																		1	D Thiem	6	6
																						5/WC	R Bautista Agut	4	3
								3	M Cecchinato	7	78
	LL	R Bemelmans	2	6	5				L Lacko	5	66
		L Lacko	6	4	7										3	M Cecchinato	60	3
		M Bašić	66	4											5/WC	R Bautista Agut	77	6
	WC	M Youzhny	78	6				WC	M Youzhny	66	6	3
	Q	L Vanni	5	2				5/WC	R Bautista Agut	78	3	6
	5/WC	R Bautista Agut	7	6

	First round							Second round							Quarterfinals							Semifinals
	6	D Džumhur	7	6
	Q	L Miedler	5	3				6	D Džumhur	6	6
	Q	I Ivashka	6	3	4				G Pella	4	4
		G Pella	4	6	6										6	D Džumhur	3	4
		A Bedene	5	65											WC	S Wawrinka	6	6
	WC	S Wawrinka	7	77				WC	S Wawrinka	712	77
								4	K Khachanov	610	61
																						WC	S Wawrinka	6	3	5
	7	D Shapovalov	77	6																			M Kližan	4	6	7
	Q	A Menéndez Maceiras	63	2				7	D Shapovalov	78	4	6
		G García López	65	6	3				M Berrettini	66	6	0
		M Berrettini	77	2	6										7	D Shapovalov	6	5	3
		E Donskoy	4	4												M Kližan	3	7	6
		M Kližan	6	6					M Kližan	6	6
								2	F Fognini	3	4

	First round							Qualifying competition
	1	Lorenzo Sonego	6	4	5
	WC	Roman Safiullin	3	6	7
								WC	Roman Safiullin	4	4
								7	Luca Vanni	6	6
		Daniel Brands	4	6	5
	7	Luca Vanni	6	4	7

	First round							Qualifying competition
	2	Ilya Ivashka	2	78	6
	Alt	Evgeny Karlovskiy	6	66	4
								2	Ilya Ivashka	77	77
								WC	Evgenii Tiurnev	64	63
	WC	Evgenii Tiurnev	6	6
	6	Stéphane Robert	3	4

	First round							Qualifying competition
	3	Ruben Bemelmans	6	4	77
	PR	Egor Gerasimov	2	6	64
								3	Ruben Bemelmans	6	2	3
								5	Adrián Menéndez Maceiras	4	6	6
		Ivan Nedelko	2	3
	5	Adrián Menéndez Maceiras	6	6

	First round							Qualifying competition
	4	Viktor Troicki	2	3
		Lucas Miedler	6	6
									Lucas Miedler	7	6
									Uladzimir Ignatik	5	2
		Uladzimir Ignatik	7	6
	8	Alexey Vatutin	5	4

• Main draw
• Qualifying draw