# 2021 Estoril Open – Singles

Albert Ramos Viñolas defeated Cameron Norrie in the final, 4–6, 6–3, 7–6$^{(7–3)}$ to win the singles tennis title at the 2021 Estoril Open. It marked his third career ATP Tour singles title, all of which have been on clay. Norrie was aiming to win his first ATP Tour title in his second final.
Stefanos Tsitsipas was the defending champion from when the tournament was last held in 2019, but did not return to compete.

## Seeds

The top four seeds received a bye into the second round.
* Denis Shapovalov (second round)
* Cristian Garín (quarterfinals)
* Ugo Humbert (quarterfinals)
* Kei Nishikori (withdrew)
* Alexander Bublik (first round)
* Marin Čilić (semifinals)
* Albert Ramos Viñolas (champion)
* Alejandro Davidovich Fokina (semifinals)

## 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 | Final |
| 7 | Albert Ramos Viñolas | 6 | 6 | | | | | |
| 8 | Alejandro Davidovich Fokina | 1 | 4 | | | | | |
| 8 | Alejandro Davidovich Fokina | 1 | 4 | 7 | Albert Ramos Viñolas | 4 | 6 | 7$^7$ |
| | | | | | Cameron Norrie | 6 | 3 | 6$^3$ |
| 6 | Marin Čilić | 6$^5$ | 5 | | Cameron Norrie | 6 | 3 | 6$^3$ |
| | Cameron Norrie | 7$^7$ | 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 | Semifinals | Semifinals | Semifinals | Semifinals |
| | | | | | 1/WC | D Shapovalov | 4 | 6 | 4 | | | | | | | | |
| | M Giron | 4 | 7$^9$ | 4 | | C Moutet | 6 | 2 | 6 | | | | | | | | |
| | C Moutet | 6 | 6$^7$ | 6 | | | | | | | C Moutet | 4 | 3 | | | | |
| | G Simon | 5 | 3 | | | | | | | 7 | A Ramos Viñolas | 6 | 6 | | | | |
| | P-H Herbert | 7 | 6 | | | P-H Herbert | 2 | 6$^3$ | | | | | | | | | |
| | F Verdasco | 3 | 3 | | 7 | A Ramos Viñolas | 6 | 7$^7$ | | | | | | | | | |
| 7 | A Ramos Viñolas | 6 | 6 | | | | | | | | | | | 7 | A Ramos Viñolas | 6 | 6 |
| | | | | | | | | | | | | | | 8 | A Davidovich Fokina | 1 | 4 |
| | | | | | 3 | U Humbert | 6 | 3 | 6 | | | | | | | | |
| | M Cecchinato | 6 | 6 | | | M Cecchinato | 4 | 6 | 3 | | | | | | | | |
| | L Harris | 3 | 4 | | | | | | | 3 | U Humbert | 4 | 4 | | | | |
| | J Chardy | 3 | 6 | 6 | | | | | | 8 | A Davidovich Fokina | 6 | 6 | | | | |
| Q | J Munar | 6 | 3 | 4 | | J Chardy | 1 | 2 | | | | | | | | | |
| | P Andújar | 3 | 6 | 1 | 8 | A Davidovich Fokina | 6 | 6 | | | | | | | | | |
| 8 | A Davidovich Fokina | 6 | 4 | 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 |
| 6 | M Čilić | 6 | 1 | 6 | | | | | | | | | | | | | | |
| Q | C Alcaraz | 3 | 6 | 4 | 6 | M Čilić | 6$^5$ | 6 | 6 | | | | | | | | | |
| Q | N Borges | 7$^7$ | 6 | | Q | N Borges | 7$^7$ | 4 | 4 | | | | | | | | | |
| | J Thompson | 6$^5$ | 3 | | | | | | | 6 | M Čilić | 7$^9$ | 0 | | | | | |
| | K Anderson | 4 | 7$^8$ | 7$^7$ | | | | | | | K Anderson | 6$^7$ | 0$^r$ | | | | | |
| | F Tiafoe | 6 | 6$^6$ | 6$^4$ | | K Anderson | 6 | 7$^7$ | | | | | | | | | | |
| | | | | | LL | R Carballés Baena | 3 | 6$^4$ | | | | | | | | | | |
| | | | | | | | | | | | | | | | 6 | M Čilić | 6$^5$ | 5 |
| 5 | A Bublik | 3 | 0 | | | | | | | | | | | | | C Norrie | 7$^7$ | 7 |
| Q | P Martínez | 6 | 6 | | Q | P Martínez | 6 | 6$^1$ | 5 | | | | | | | | | |
| | C Norrie | 6 | 6 | | | C Norrie | 4 | 7$^7$ | 7 | | | | | | | | | |
| WC | J Sousa | 1 | 3 | | | | | | | | C Norrie | 3 | 7 | 6 | | | | |
| | JI Londero | 3 | 5 | | | | | | | 2 | C Garín | 6 | 5 | 3 | | | | |
| | R Gasquet | 6 | 7 | | | R Gasquet | | | | | | | | | | | | |
| | | | | | 2 | C Garín | w/o | | | | | | | | | | | |

## Qualifying
### Seeds

* Jaume Munar (qualified)
* Roberto Carballés Baena (qualifying competition, lucky loser)
* Juan Ignacio Londero (moved to main draw)
* Pedro Martínez (qualified)
* Pedro Sousa (first round)
* Carlos Alcaraz (qualified)
* Brandon Nakashima (first round)
* Liam Broady (first round)

### Qualifiers

* Jaume Munar
* Nuno Borges
* Carlos Alcaraz
* Pedro Martínez

### Lucky loser

* Roberto Carballés Baena

### Qualifying draw
#### First qualifier

| First round | First round | First round | First round | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition |
| 1 | Jaume Munar | 6 | 7$^7$ | | | | |
| | Thomas Fabbiano | 4 | 6$^5$ | | | | |
| | Thomas Fabbiano | 4 | 6$^5$ | 1 | Jaume Munar | 7$^8$ | 6 |
| | | | | WC | Frederico Ferreira Silva | 6$^6$ | 3 |
| WC | Frederico Ferreira Silva | 6 | 6 | WC | Frederico Ferreira Silva | 6$^6$ | 3 |
| 7 | Brandon Nakashima | 2 | 3 | | | | |

#### Second qualifier

| First round | First round | First round | First round | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition |
| 2 | Roberto Carballés Baena | 7 | 7 | | | | |
| | Henri Laaksonen | 5 | 5 | | | | |
| | Henri Laaksonen | 5 | 5 | 2 | Roberto Carballés Baena | 5 | 4 |
| | | | | WC | Nuno Borges | 7 | 6 |
| WC | Nuno Borges | 6 | 7 | WC | Nuno Borges | 7 | 6 |
| 8 | Liam Broady | 3 | 5 | | | | |

#### Third qualifier

| First round | First round | First round | First round | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition |
| Alt | João Domingues | 4 | 2 | | | | |
| | Carlos Taberner | 6 | 6 | | | | |
| | Carlos Taberner | 6 | 6 | | Carlos Taberner | 5 | 3 |
| | | | | 6 | Carlos Alcaraz | 7 | 6 |
| | Tallon Griekspoor | 1 | 3 | 6 | Carlos Alcaraz | 7 | 6 |
| 6 | Carlos Alcaraz | 6 | 6 | | | | |

#### Fourth qualifier

| First round | First round | First round | First round | First round | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition |
| 4 | Pedro Martínez | 6 | 6$^4$ | 6 | | | | |
| | Botic van de Zandschulp | 4 | 7$^7$ | 1 | | | | |
| | Botic van de Zandschulp | 4 | 7$^7$ | 1 | 4 | Pedro Martínez | 7 | 7 |
| | | | | | | Marc-Andrea Hüsler | 5 | 5 |
| | Marc-Andrea Hüsler | 6 | 6 | | | Marc-Andrea Hüsler | 5 | 5 |
| 5 | Pedro Sousa | 2 | 4 | | | | | |