The 2018 St. Petersburg Open was a tennis tournament played on indoor hard courts. It was the 23rd edition of the St. Petersburg Open, and part of the ATP World Tour 250 Series of the 2018 ATP World Tour. It took place at the Sibur Arena in Saint Petersburg, Russia, from September 17 through 23, 2018.
Singles main-draw entrants
Seeds
1 Rankings are as of September 10, 2018
Other entrants
The following players received wildcards into the singles main draw: Roberto Bautista Agut Stan Wawrinka Mikhail Youzhny
The following players received entry from the qualifying draw: Ilya Ivashka Adrián Menéndez Maceiras Lucas Miedler Luca Vanni
The following player received entry as a lucky loser: Ruben Bemelmans
Withdrawals
Before the tournament
Marcos Baghdatis → replaced by Ruben Bemelmans
Jozef Kovalík → replaced by Marcos Baghdatis
Leonardo Mayer → replaced by Evgeny Donskoy
Doubles main-draw entrants
Seeds
Rankings are as of September 10, 2018
Other entrants
The following pairs received wildcards into the doubles main draw: Mikhail Elgin / Denis Istomin Teymuraz Gabashvili / Evgeny Karlovskiy
Withdrawals
During the tournament
Denis Istomin
Champions
Singles
Dominic Thiem def. Martin Kližan, 6–3, 6–1
Doubles
Matteo Berrettini / Fabio Fognini def. Roman Jebavý / Matwé Middelkoop, 7–6(8–6), 7–6(7–4)