# 2020 Lisboa Belém Open – Singles

Roberto Carballés Baena was the defending champion but chose not to defend his title.
Jaume Munar won the title after defeating Pedro Sousa 7–6$^{(7–3)}$, 6–2 in the final.

## Seeds

* Jaume Munar (champion)
* Pedro Sousa (final)
* Damir Džumhur (first round)
* Paolo Lorenzi (second round)
* Federico Gaio (semifinals)
* Tallon Griekspoor (second round, retired)
* Blaž Rola (first round)
* João Domingues (first 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 | Final | Final | Final | Final |
| 1 | Jaume Munar | 6 | 6 | | | | |
| 5 | Federico Gaio | 3 | 0 | | | | |
| 5 | Federico Gaio | 3 | 0 | 1 | Jaume Munar | 7$^7$ | 6 |
| | | | | 2 | Pedro Sousa | 6$^3$ | 2 |
| | Alessandro Giannessi | 4 | 4 | 2 | Pedro Sousa | 6$^3$ | 2 |
| 2 | Pedro Sousa | 6 | 6 | | | | |

### Top half

| First round | First round | First round | First round | First round | Second round | Second round | Second round | Second round | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Semifinals | Semifinals | Semifinals | Semifinals |
| 1 | J Munar | 6 | 6 | | | | | | | | | | | | | | |
| Q | S Ofner | 4 | 2 | | 1 | J Munar | 6 | 7$^7$ | | | | | | | | | |
| | Q Halys | 2 | 4 | | Q | B Gojo | 1 | 6$^5$ | | | | | | | | | |
| Q | B Gojo | 6 | 6 | | | | | | 1 | J Munar | 6 | 6 | | | | | |
| | J Clarke | 1 | 6 | 3 | | | | | | A Müller | 2 | 2 | | | | | |
| | A Müller | 6 | 3 | 6 | | A Müller | 6 | 0 | | | | | | | | | |
| | C Lestienne | 5 | 6 | 3 | 6 | T Griekspoor | 1 | 1$^r$ | | | | | | | | | |
| 6 | T Griekspoor | 7 | 2 | 6 | | | | | | | | | | 1 | J Munar | 6 | 6 |
| 3/SE | D Džumhur | 6$^8$ | 1 | | | | | | | | | | | 5 | F Gaio | 3 | 0 |
| WC | N Borges | 7$^{10}$ | 6 | | WC | N Borges | 3 | 6$^5$ | | | | | | | | | |
| | M Janvier | 6$^8$ | 2 | | Q | G Clezar | 6 | 7$^7$ | | | | | | | | | |
| Q | G Clezar | 7$^{10}$ | 6 | | | | | | Q | G Clezar | 7 | 4 | 6$^4$ | | | | |
| | E Benchetrit | 6 | 7$^9$ | | | | | | 5 | F Gaio | 5 | 6 | 7$^7$ | | | | |
| | R Olivo | 3 | 6$^7$ | | | E Benchetrit | 4 | 5 | | | | | | | | | |
| | Z Kolář | 3 | 3 | | 5 | F Gaio | 6 | 7 | | | | | | | | | |
| 5 | F Gaio | 6 | 6 | | | | | | | | | | | | | | |

### Bottom half

| First round | First round | First round | First round | First round | Second round | Second round | Second round | Second round | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Semifinals | Semifinals | Semifinals | Semifinals |
| 8 | J Domingues | 3 | 0 | | | | | | | | | | | | | |
| | B Bonzi | 6 | 6 | | | B Bonzi | 5 | 2 | | | | | | | | |
| | F Ferreira Silva | 5 | 3 | | Q | D Kuzmanov | 7 | 6 | | | | | | | | |
| Q | D Kuzmanov | 7 | 6 | | | | | | Q | D Kuzmanov | 4 | 3 | | | | |
| | A Giannessi | 6 | 5 | 6 | | | | | | A Giannessi | 6 | 6 | | | | |
| | R Cid Subervi | 3 | 7 | 2 | | A Giannessi | 7 | 6 | | | | | | | | |
| | U Blanch | 2 | 3 | | 4 | P Lorenzi | 5 | 3 | | | | | | | | |
| 4 | P Lorenzi | 6 | 6 | | | | | | | | | | | A Giannessi | 4 | 4 |
| 7 | B Rola | 6 | 6$^2$ | 5 | | | | | | | | | 2 | P Sousa | 6 | 6 |
| WC | G Oliveira | 1 | 7$^7$ | 7 | WC | G Oliveira | 2 | 2 | | | | | | | | |
| | J Menezes | 3 | 4 | | | D Popko | 6 | 6 | | | | | | | | |
| | D Popko | 6 | 6 | | | | | | | D Popko | 5 | 2 | | | | |
| | H Grenier | 5 | 6 | 6 | | | | | 2 | P Sousa | 7 | 6 | | | | |
| | M Bourgue | 7 | 0 | 1 | | H Grenier | 5 | 0 | | | | | | | | |
| WC | G Elias | 7$^7$ | 1 | 3 | 2 | P Sousa | 7 | 6 | | | | | | | | |
| 2 | P Sousa | 6$^5$ | 6 | 6 | | | | | | | | | | | | |