# 2021 Geneva Open – Singles

Alexander Zverev was the defending champion from when the event was held in 2019, but chose not to defend his title.
Casper Ruud won the title, defeating Denis Shapovalov in the final, 7–6$^{(8–6)}$, 6–4.

## Seeds

The top four seeds received a bye into the second round.
* Roger Federer (second round)
* Denis Shapovalov (final)
* Casper Ruud (champion)
* Grigor Dimitrov (quarterfinals)
* Cristian Garín (withdrew)
* Fabio Fognini (second round)
* Benoît Paire (first round)
* Adrian Mannarino (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 |
| | Pablo Andújar | 3 | 2 | | | | |
| 3 | Casper Ruud | 6 | 6 | | | | |
| 3 | Casper Ruud | 6 | 6 | 3 | Casper Ruud | 7$^8$ | 6 |
| | | | | 2 | Denis Shapovalov | 6$^6$ | 4 |
| Q | Pablo Cuevas | 4 | 5 | 2 | Denis Shapovalov | 6$^6$ | 4 |
| 2 | Denis Shapovalov | 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 | R Federer | 4 | 6 | 4 | | | | | | | | | |
| | J Thompson | 0 | 4 | | | P Andújar | 6 | 4 | 6 | | | | | | | | | |
| | P Andújar | 6 | 6 | | | | | | | | P Andújar | 4 | 6 | 6 | | | | |
| | M Čilić | 6$^5$ | 1 | | | | | | | WC | D Stricker | 6 | 4 | 4 | | | | |
| WC | D Stricker | 7$^7$ | 6 | | WC | D Stricker | 7 | 6 | | | | | | | | | | |
| | M Fucsovics | 7 | 7 | | | M Fucsovics | 5 | 4 | | | | | | | | | | |
| Q | H Laaksonen | 5 | 5 | | | | | | | | | | | | | P Andújar | 3 | 2 |
| | | | | | | | | | | | | | | | 3 | C Ruud | 6 | 6 |
| | | | | | 3 | C Ruud | 7 | 6 | | | | | | | | | | |
| | T Sandgren | 6 | 6 | | | T Sandgren | 5 | 2 | | | | | | | | | | |
| | S Caruso | 3 | 4 | | | | | | | 3 | C Ruud | 2 | 6 | 6 | | | | |
| | F López | 7$^8$ | 6 | | | | | | | | D Koepfer | 6 | 1 | 4 | | | | |
| LL | D Altmaier | 6$^6$ | 4 | | | F López | 5 | 7$^7$ | 3 | | | | | | | | | |
| | D Koepfer | 6$^8$ | 7$^7$ | 6 | | D Koepfer | 7 | 6$^1$ | 6 | | | | | | | | | |
| 7 | B Paire | 7$^{10}$ | 6$^5$ | 4 | | | | | | | | | | | | | | |

### 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 |
| 8 | A Mannarino | 3 | 7$^7$ | 3 | | | | | | | | | | | | | |
| WC | A Cazaux | 6 | 6$^5$ | 6 | WC | A Cazaux | 2 | 4 | | | | | | | | | |
| Q | P Cuevas | 7$^7$ | 6 | | Q | P Cuevas | 6 | 6 | | | | | | | | | |
| | R Opelka | 6$^5$ | 2 | | | | | | | Q | P Cuevas | 7$^7$ | 6 | | | | |
| | F Verdasco | 6$^5$ | 4 | | | | | | | 4/WC | G Dimitrov | 6$^3$ | 3 | | | | |
| Q | I Ivashka | 7$^7$ | 6 | | Q | I Ivashka | 4 | 4 | | | | | | | | | |
| | | | | | 4/WC | G Dimitrov | 6 | 6 | | | | | | | | | |
| | | | | | | | | | | | | | | Q | P Cuevas | 4 | 5 |
| 6 | F Fognini | 6 | 6 | | | | | | | | | | | 2 | D Shapovalov | 6 | 7 |
| | G Pella | 2 | 2 | | 6 | F Fognini | 3 | 7$^7$ | 1 | | | | | | | | |
| | T Monteiro | 7$^9$ | 3 | 5 | | L Đere | 6 | 6$^2$ | 6 | | | | | | | | |
| | L Đere | 6$^7$ | 6 | 7 | | | | | | | L Đere | 4 | 4 | | | | |
| | S Travaglia | 3 | 0$^r$ | | | | | | | 2 | D Shapovalov | 6 | 6 | | | | |
| Q | M Cecchinato | 6 | 3 | | Q | M Cecchinato | 7$^7$ | 5 | 1 | | | | | | | | |
| | | | | | 2 | D Shapovalov | 6$^4$ | 7 | 6 | | | | | | | | |

## Qualifying
### Seeds

* Ilya Ivashka (qualified)
* Marco Cecchinato (qualified)
* Mikhail Kukushkin (first round)
* Pablo Cuevas (qualified)
* Mackenzie McDonald (qualifying competition)
* Peter Gojowczyk (first round)
* Cedrik-Marcel Stebe (first round)
* Daniel Altmaier (qualifying competition, lucky loser)

### Qualifiers

* Ilya Ivashka
* Marco Cecchinato
* Henri Laaksonen
* Pablo Cuevas

### Lucky loser

* Daniel Altmaier

### Qualifying draw
#### First qualifier

| First round | First round | First round | First round | First round | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition |
| 1 | Ilya Ivashka | 6 | 6 | | | | | |
| WC | Li Hanwen | 0 | 3 | | | | | |
| WC | Li Hanwen | 0 | 3 | | 1 | Ilya Ivashka | 6 | 6 |
| | | | | | 5 | Mackenzie McDonald | 4 | 3 |
| | Prajnesh Gunneswaran | 3 | 6 | 3 | 5 | Mackenzie McDonald | 4 | 3 |
| 5 | Mackenzie McDonald | 6 | 3 | 6 | | | | |

#### Second qualifier

| First round | First round | First round | First round | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition |
| 2 | Marco Cecchinato | 6 | 6 | | | | |
| | Illya Marchenko | 3 | 4 | | | | |
| | Illya Marchenko | 3 | 4 | 2 | Marco Cecchinato | 6 | 7$^7$ |
| | | | | 8 | Daniel Altmaier | 1 | 6$^5$ |
| | Marc-Andrea Hüsler | 6$^5$ | 2 | 8 | Daniel Altmaier | 1 | 6$^5$ |
| 8 | Daniel Altmaier | 7$^7$ | 6 | | | | |

#### Third qualifier

| First round | First round | First round | First round | First round | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition |
| 3 | Mikhail Kukushkin | 3 | 1 | | | | | |
| | Alejandro Tabilo | 6 | 6 | | | | | |
| | Alejandro Tabilo | 6 | 6 | | Alejandro Tabilo | 6 | 1 | 3 |
| | | | | | Henri Laaksonen | 2 | 6 | 6 |
| | Henri Laaksonen | 6 | 5 | 6 | Henri Laaksonen | 2 | 6 | 6 |
| 7 | Cedrik-Marcel Stebe | 4 | 7 | 0 | | | | |

#### Fourth qualifier

| First round | First round | First round | First round | First round | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition |
| 4 | Pablo Cuevas | 6 | 4 | 6 | | | | |
| WC | Jakub Paul | 3 | 6 | 3 | | | | |
| WC | Jakub Paul | 3 | 6 | 3 | 4 | Pablo Cuevas | 6 | 6 |
| | | | | | | Lorenzo Giustino | 2 | 4 |
| | Lorenzo Giustino | 6 | 6 | | | Lorenzo Giustino | 2 | 4 |
| 6 | Peter Gojowczyk | 2 | 3 | | | | | |