# 2018 Lisboa Belém Open – Singles

Oscar Otte was the defending champion but chose not to defend his title.
Tommy Robredo won the title after defeating Cristian Garín 3–6, 6–3, 6–2 in the final.

## Seeds

* Taro Daniel (quarterfinals)
* Alex de Minaur (first round)
* Gastão Elias (withdrew)
* Pedro Sousa (semifinals)
* Marcelo Arévalo (first round)
* Sebastian Ofner (semifinals)
* Liam Broady (second round)
* Jaume Munar (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 |
| | Cristian Garín | 5 | 7 | 6 | | | | |
| 4 | Pedro Sousa | 7 | 5 | 4 | | | | |
| 4 | Pedro Sousa | 7 | 5 | 4 | Cristian Garín | 6 | 3 | 2 |
| | | | | | Tommy Robredo | 3 | 6 | 6 |
| 6 | Sebastian Ofner | 6 | 4 | 1 | Tommy Robredo | 3 | 6 | 6 |
| | Tommy Robredo | 3 | 6 | 6 | | | | |

### 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 | Semifinals |
| 1/WC | T Daniel | 7$^7$ | 7$^7$ | | | | | | | | | | | | | | | | |
| WC | João Monteiro | 6$^4$ | 6$^2$ | | 1/WC | T Daniel | 6 | 3 | 7$^7$ | | | | | | | | | | |
| Q | Edoardo Eremin | 5 | 6 | 4 | | L Rosol | 1 | 6 | 6$^4$ | | | | | | | | | | |
| | L Rosol | 7 | 3 | 6 | | | | | | 1/WC | T Daniel | 6 | 1 | 0 | | | | | |
| Q | JP Ficovich | 3 | 5 | | | | | | | | C Garín | 4 | 6 | 6 | | | | | |
| | C Garín | 6 | 7 | | | C Garín | 6 | 7$^7$ | | | | | | | | | | | |
| | R Olivo | 1 | 1$^r$ | | 8 | J Munar | 4 | 6$^4$ | | | | | | | | | | | |
| 8 | J Munar | 6 | 4 | | | | | | | | | | | | | C Garín | 5 | 7 | 6 |
| 4 | P Sousa | 6 | 7 | | | | | | | | | | | | 4 | P Sousa | 7 | 5 | 4 |
| WC | F Gil | 2 | 5 | | 4 | P Sousa | 6 | 6 | | | | | | | | | | | |
| | L Giustino | 7 | 1 | 7$^9$ | | L Giustino | 2 | 0 | | | | | | | | | | | |
| Q | J De Loore | 5 | 6 | 6$^7$ | | | | | | 4 | P Sousa | 6 | 6 | | | | | | |
| | G Oliveira | 3 | 5 | | | | | | | | F Auger-Aliassime | 3 | 1 | | | | | | |
| | F Auger-Aliassime | 6 | 7 | | | F Auger-Aliassime | 6 | 7 | | | | | | | | | | | |
| | J Domingues | 6 | 6 | | | J Domingues | 4 | 5 | | | | | | | | | | | |
| 5 | M Arévalo | 2 | 2 | | | | | | | | | | | | | | | | |

### Bottom half

| 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 |
| 6 | S Ofner | 6 | 6 | | | | | | | | | | | | | | |
| WC | T Cação | 0 | 3 | 6 | S Ofner | 6 | 6 | | | | | | | | | | |
| | E King | 3 | 0 | | M Krueger | 3 | 4 | | | | | | | | | | |
| | M Krueger | 6 | 6 | | | | | | 6 | S Ofner | 6 | 7 | | | | | |
| | M Kecmanović | 6 | 7$^7$ | | | | | | | M Kecmanović | 4 | 5 | | | | | |
| | T Bellucci | 3 | 6$^4$ | | M Kecmanović | 6 | 6 | | | | | | | | | | |
| | D Novak | 6$^5$ | 1 | LL | F Gaio | 4 | 2 | | | | | | | | | | |
| LL | F Gaio | 7$^7$ | 6 | | | | | | | | | | 6 | S Ofner | 6 | 4 | 1 |
| 7 | L Broady | 7$^7$ | 6 | | | | | | | | | | | T Robredo | 3 | 6 | 6 |
| | S Robert | 6$^3$ | 4 | 7 | L Broady | 3 | 6 | 3 | | | | | | | | | |
| | T Robredo | 6 | 6 | | T Robredo | 6 | 4 | 6 | | | | | | | | | |
| | R Ojeda Lara | 2 | 2 | | | | | | | T Robredo | 7 | 6 | | | | | |
| | C Harrison | 6 | 6 | | | | | | | C Harrison | 5 | 1 | | | | | |
| | G Sakharov | 0 | 4 | | C Harrison | 5 | 7$^{10}$ | 6 | | | | | | | | | |
| Q | A Davidovich Fokina | 7$^7$ | 6 | Q | A Davidovich Fokina | 7 | 6$^8$ | 1 | | | | | | | | | |
| 2 | A de Minaur | 6$^5$ | 4 | | | | | | | | | | | | | | |