# 2018 Croatia Open Umag – Singles

Andrey Rublev was the defending champion, but lost in the quarterfinals to Robin Haase. This was Rublev's first tournament back on tour after missing three months due to a stress fracture in his back.
Marco Cecchinato won the title, defeating Guido Pella in the final, 6–2, 7–6$^{(7–4)}$.

## Seeds

The top four seeds receive a bye into the second round.
* Kyle Edmund (withdrew due to a throat infection)
* Damir Džumhur (second round)
* Marco Cecchinato (champion)
* Andrey Rublev (quarterfinals)
* Albert Ramos Viñolas (second round)
* Robin Haase (semifinals)
* João Sousa (first round)
* Benoît Paire (first round)
* Maximilian Marterer (second round)

## 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 |
| | Guido Pella | 6 | 1 | 6 | | | | |
| 6 | Robin Haase | 3 | 6 | 2 | | | | |
| 6 | Robin Haase | 3 | 6 | 2 | | Guido Pella | 2 | 6$^4$ |
| | | | | | 3 | Marco Cecchinato | 6 | 7$^7$ |
| 3 | Marco Cecchinato | 6 | 6 | | 3 | Marco Cecchinato | 6 | 7$^7$ |
| Q | Marco Trungelliti | 2 | 1 | | | | | |

### 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 | Semifinals | Semifinals | Semifinals | Semifinals | Semifinals |
| | | | | | 5 | A Ramos Viñolas | 3 | 6 | 0 | | | | | | | | | |
| | D Lajović | 7 | 6 | | | D Lajović | 6 | 1 | 6 | | | | | | | | | |
| | N Basilashvili | 5 | 2 | | | | | | | | D Lajović | 6$^3$ | 5 | | | | | |
| | G Pella | 1 | 6 | 6 | | | | | | | G Pella | 7$^7$ | 7 | | | | | |
| | T Daniel | 6 | 3 | 3 | | G Pella | 5 | 6 | 6 | | | | | | | | | |
| | A Bedene | 7$^7$ | 4 | 6 | | A Bedene | 7 | 4 | 4 | | | | | | | | | |
| 7 | J Sousa | 6$^5$ | 6 | 4 | | | | | | | | | | | G Pella | 6 | 1 | 6 |
| | | | | | | | | | | | | | | 6 | R Haase | 3 | 6 | 2 |
| | | | | | 4 | A Rublev | 6 | 6$^4$ | 6 | | | | | | | | | |
| WC | F Auger-Aliassime | 6 | 6 | | WC | F Auger-Aliassime | 4 | 7$^7$ | 3 | | | | | | | | | |
| LL | A Martin | 4 | 3 | | | | | | | 4 | A Rublev | 3 | 6$^6$ | | | | | |
| Q | M Kližan | 6 | 6 | | | | | | | 6 | R Haase | 6 | 7$^8$ | | | | | |
| | N Jarry | 2 | 0 | | Q | M Kližan | 6 | 4 | 3 | | | | | | | | | |
| Q | R Dutra Silva | 6 | 5 | 3 | 6 | R Haase | 3 | 6 | 6 | | | | | | | | | |
| 6 | R Haase | 4 | 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 | Semifinals | Semifinals | Semifinals | Semifinals |
| 9 | M Marterer | 3 | 7 | 6 | | | | | | | | | | | | | |
| WC | N Serdarušić | 6 | 5 | 3 | 9 | M Marterer | 6$^4$ | 3 | | | | | | | | | |
| | L Đere | 6 | 1 | 6 | | L Đere | 7$^7$ | 6 | | | | | | | | | |
| | P Cuevas | 4 | 6 | 3 | | | | | | | L Đere | 4 | 1 | | | | |
| Q | S Travaglia | 3 | 6 | 2 | | | | | | 3 | M Cecchinato | 6 | 6 | | | | |
| | J Veselý | 6 | 3 | 6 | | J Veselý | 6 | 5 | 5 | | | | | | | | |
| | | | | | 3 | M Cecchinato | 2 | 7 | 7 | | | | | | | | |
| | | | | | | | | | | | | | | 3 | M Cecchinato | 6 | 6 |
| 8 | B Paire | 1 | 3 | | | | | | | | | | | Q | M Trungelliti | 2 | 1 |
| | M Fucsovics | 6 | 6 | | | M Fucsovics | 7 | 4 | 2 | | | | | | | | |
| Q | M Trungelliti | 6 | 6 | | Q | M Trungelliti | 5 | 6 | 6 | | | | | | | | |
| WC | F Škugor | 3 | 4 | | | | | | | Q | M Trungelliti | 6 | 6 | | | | |
| | P Lorenzi | 3 | 4 | | | | | | | | E Donskoy | 1 | 4 | | | | |
| | E Donskoy | 6 | 6 | | | E Donskoy | 7$^{11}$ | 3 | 6 | | | | | | | | |
| | | | | | 2 | D Džumhur | 6$^9$ | 6 | 4 | | | | | | | | |

## Qualifying
### Seeds

* Martin Kližan (qualified)
* Rogério Dutra Silva (qualified)
* Alexey Vatutin (qualifying competition, retired)
* Stefano Travaglia (qualified)
* Facundo Bagnis (first round)
* Enrique López Pérez (first round, retired)
* Andrej Martin (qualifying competition, lucky loser)
* Kenny de Schepper (qualifying competition)

### Qualifiers

* Martin Kližan
* Rogério Dutra Silva
* Marco Trungelliti
* Stefano Travaglia

### Lucky loser

* Andrej Martin

### Qualifying draw
#### First qualifier

| First round | First round | First round | First round | First round | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition |
| 1 | Martin Kližan | 2 | 7$^7$ | 6 | | | | |
| | Danilo Petrović | 6 | 6$^2$ | 4 | | | | |
| | Danilo Petrović | 6 | 6$^2$ | 4 | 1 | Martin Kližan | 6 | 6 |
| | | | | | 8 | Kenny de Schepper | 4 | 2 |
| | Zsombor Piros | 2 | 6$^5$ | | 8 | Kenny de Schepper | 4 | 2 |
| 8 | Kenny de Schepper | 6 | 7$^7$ | | | | | |

#### Second qualifier

| First round | First round | First round | First round | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition |
| 2 | Rogério Dutra Silva | 6 | 6 | | | | | |
| WC | Admir Kalender | 3 | 2 | | | | | |
| WC | Admir Kalender | 3 | 2 | 2 | Rogério Dutra Silva | 6 | 5 | 6 |
| | | | | 7 | Andrej Martin | 2 | 7 | 2 |
| | Roberto Quiroz | 2 | 6$^0$ | 7 | Andrej Martin | 2 | 7 | 2 |
| 7 | Andrej Martin | 6 | 7$^7$ | | | | | |

#### Third qualifier

| First round | First round | First round | First round | Qualifying competition | Qualifying competition | Qualifying competition |
| 3 | Alexey Vatutin | 6 | 6 | | | |
| Alt | Nik Razboršek | 2 | 3 | | | |
| Alt | Nik Razboršek | 2 | 3 | 3 | Alexey Vatutin | 2$^r$ |
| | | | | | Marco Trungelliti | 3 |
| | Marco Trungelliti | 7$^7$ | 6 | | Marco Trungelliti | 3 |
| 5 | Facundo Bagnis | 6$^4$ | 3 | | | |

#### Fourth qualifier

| First round | First round | First round | First round | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition |
| 4 | Stefano Travaglia | 7$^7$ | 7$^7$ | | | | | |
| | Gian Marco Moroni | 6$^3$ | 6$^1$ | | | | | |
| | Gian Marco Moroni | 6$^3$ | 6$^1$ | 4 | Stefano Travaglia | 1 | 6 | 6 |
| | | | | | Peđa Krstin | 6 | 3 | 2 |
| | Peđa Krstin | 3 | | | Peđa Krstin | 6 | 3 | 2 |
| 6 | Enrique López Pérez | 1$^r$ | | | | | | |