# 2018 St. Petersburg Open – Singles

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.

## Seeds

The top four seeds receive a bye into the second round.
* Dominic Thiem (champion)
* Fabio Fognini (second round)
* Marco Cecchinato (quarterfinals)
* Karen Khachanov (second round)
* Roberto Bautista Agut (semifinals)
* Damir Džumhur (quarterfinals)
* Denis Shapovalov (quarterfinals)
* Daniil Medvedev (quarterfinals)

## Draw
### Key

* Q = Qualifier
* WC = Wild card
* LL = Lucky loser
* Alt = Alternate
* SE = Special exempt
* PR = Protected ranking
* ITF = ITF entry
* JE = Junior exempt
* w/o = Walkover
* r = Retired
* d = Defaulted
* SR = Special ranking

### Finals

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

### Top half

| First round | First round | First round | First round | First round | Second round | Second round | Second round | Second round | Second round | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Semifinals | Semifinals | Semifinals | Semifinals |
| | | | | | 1 | D Thiem | 7$^7$ | 6 | | | | | | | | | | |
| | A Rublev | 4 | 6$^6$ | | | J-L Struff | 6$^4$ | 4 | | | | | | | | | | |
| | J-L Struff | 6 | 7$^8$ | | | | | | | 1 | D Thiem | 6 | 3 | 7$^7$ | | | | |
| | M Kukushkin | 7 | 2 | | | | | | | 8 | D Medvedev | 2 | 6 | 6$^2$ | | | | |
| | D Istomin | 5 | 4$^r$ | | | 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 | 7$^8$ | | | | | | | | | | |
| LL | R Bemelmans | 2 | 6 | 5 | | L Lacko | 5 | 6$^6$ | | | | | | | | | | |
| | L Lacko | 6 | 4 | 7 | | | | | | 3 | M Cecchinato | 6$^0$ | 3 | | | | | |
| | M Bašić | 6$^6$ | 4 | | | | | | | 5/WC | R Bautista Agut | 7$^7$ | 6 | | | | | |
| WC | M Youzhny | 7$^8$ | 6 | | WC | M Youzhny | 6$^6$ | 6 | 3 | | | | | | | | | |
| Q | L Vanni | 5 | 2 | | 5/WC | R Bautista Agut | 7$^8$ | 3 | 6 | | | | | | | | | |
| 5/WC | R Bautista Agut | 7 | 6 | | | | | | | | | | | | | | | |

### Bottom half

| First round | First round | First round | First round | First round | Second round | Second round | Second round | Second round | Second round | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Semifinals | Semifinals | Semifinals | Semifinals | 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 | 6$^5$ | | | | | | | WC | S Wawrinka | 6 | 6 | | | | | | |
| WC | S Wawrinka | 7 | 7$^7$ | | WC | S Wawrinka | 7$^{12}$ | 7$^7$ | | | | | | | | | | | |
| | | | | | 4 | K Khachanov | 6$^{10}$ | 6$^1$ | | | | | | | | | | | |
| | | | | | | | | | | | | | | | WC | S Wawrinka | 6 | 3 | 5 |
| 7 | D Shapovalov | 7$^7$ | 6 | | | | | | | | | | | | | M Kližan | 4 | 6 | 7 |
| Q | A Menéndez Maceiras | 6$^3$ | 2 | | 7 | D Shapovalov | 7$^8$ | 4 | 6 | | | | | | | | | | |
| | G García López | 6$^5$ | 6 | 3 | | M Berrettini | 6$^6$ | 6 | 0 | | | | | | | | | | |
| | M Berrettini | 7$^7$ | 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 | | | | | | | | | | | |

## Qualifying
### Seeds

* Lorenzo Sonego (first round)
* Ilya Ivashka (qualified)
* Ruben Bemelmans (qualifying competition, lucky loser)
* Viktor Troicki (first round)
* Adrián Menéndez Maceiras (qualified)
* Stéphane Robert (first round)
* Luca Vanni (qualified)
* Alexey Vatutin (first round)

### Qualifiers

* Luca Vanni
* Ilya Ivashka
* Adrián Menéndez Maceiras
* Lucas Miedler

### Lucky loser

* Ruben Bemelmans

### Qualifying draw
#### First qualifier

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

#### Second qualifier

| First round | First round | First round | First round | First round | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition |
| 2 | Ilya Ivashka | 2 | 7$^8$ | 6 | | | | |
| Alt | Evgeny Karlovskiy | 6 | 6$^6$ | 4 | | | | |
| Alt | Evgeny Karlovskiy | 6 | 6$^6$ | 4 | 2 | Ilya Ivashka | 7$^7$ | 7$^7$ |
| | | | | | WC | Evgenii Tiurnev | 6$^4$ | 6$^3$ |
| WC | Evgenii Tiurnev | 6 | 6 | | WC | Evgenii Tiurnev | 6$^4$ | 6$^3$ |
| 6 | Stéphane Robert | 3 | 4 | | | | | |

#### Third qualifier

| First round | First round | First round | First round | First round | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition |
| 3 | Ruben Bemelmans | 6 | 4 | 7$^7$ | | | | | |
| PR | Egor Gerasimov | 2 | 6 | 6$^4$ | | | | | |
| PR | Egor Gerasimov | 2 | 6 | 6$^4$ | 3 | Ruben Bemelmans | 6 | 2 | 3 |
| | | | | | 5 | Adrián Menéndez Maceiras | 4 | 6 | 6 |
| | Ivan Nedelko | 2 | 3 | | 5 | Adrián Menéndez Maceiras | 4 | 6 | 6 |
| 5 | Adrián Menéndez Maceiras | 6 | 6 | | | | | | |

#### Fourth qualifier

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