# 2021 Garden Open – Singles

Henri Laaksonen was the defending champion but chose not to defend his title.
Andrea Pellegrino won the title after defeating Hugo Gaston 3–6, 6–2, 6–1 in the final.

## Seeds

* Grégoire Barrère (first round)
* Hugo Dellien (first round)
* Paolo Lorenzi (second round)
* Sebastian Ofner (quarterfinals)
* Hugo Gaston (final)
* Juan Pablo Varillas (semifinals)
* Lorenzo Giustino (quarterfinals)
* Steven Diez (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 | Semifinals | Final | Final | Final | Final | Final |
| 6 | Juan Pablo Varillas | 4 | 5 | | | | | | |
| 5 | Hugo Gaston | 6 | 7 | | | | | | |
| 5 | Hugo Gaston | 6 | 7 | | 5 | Hugo Gaston | 6 | 2 | 1 |
| | | | | | WC | Andrea Pellegrino | 3 | 6 | 6 |
| WC | Andrea Pellegrino | 3 | 6 | 6 | WC | Andrea Pellegrino | 3 | 6 | 6 |
| Q | Vít Kopřiva | 6 | 1 | 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 |
| 1 | G Barrère | 6$^4$ | 4 | | | | | | | | | | | | | | |
| | G Andreozzi | 7$^7$ | 6 | | | G Andreozzi | 5 | 7$^8$ | 2 | | | | | | | | |
| | E Couacaud | 3 | 3 | | | E Ymer | 7 | 6$^6$ | 6 | | | | | | | | |
| | E Ymer | 6 | 6 | | | | | | | | E Ymer | 4 | 3 | | | | |
| Alt | B Gojo | 2 | 3 | | | | | | | 6 | JP Varillas | 6 | 6 | | | | |
| | R Marcora | 6 | 6 | | | R Marcora | 3 | 0 | | | | | | | | | |
| Alt | A Collarini | 2 | 6 | 2 | 6 | JP Varillas | 6 | 6 | | | | | | | | | |
| 6 | JP Varillas | 6 | 3 | 6 | | | | | | | | | | 6 | JP Varillas | 4 | 5 |
| 3 | P Lorenzi | 7$^7$ | 2 | 6 | | | | | | | | | | 5 | H Gaston | 6 | 7 |
| | Y Maden | 6$^4$ | 6 | 3 | 3 | P Lorenzi | 6 | 1 | 5 | | | | | | | | |
| | A Bolt | 3 | 4 | | Q | T Lamasine | 4 | 6 | 7 | | | | | | | | |
| Q | T Lamasine | 6 | 6 | | | | | | | Q | T Lamasine | 2 | 6$^6$ | | | | |
| PR | T Kokkinakis | 6 | 6 | | | | | | | 5 | H Gaston | 6 | 7$^8$ | | | | |
| | J Clarke | 2 | 4 | | PR | T Kokkinakis | 2 | 3 | | | | | | | | | |
| | E Escobedo | 3 | 4 | | 5 | H Gaston | 6 | 6 | | | | | | | | | |
| 5 | H Gaston | 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 | Quarterfinals | Semifinals | Semifinals | Semifinals | Semifinals | Semifinals |
| 8 | S Diez | 6 | 2 | 3 | | | | | | | | | | | | | | |
| WC | A Pellegrino | 1 | 6 | 6 | WC | A Pellegrino | 7$^9$ | 6 | | | | | | | | | | |
| Q | F Cobolli | 7 | 5 | | Q | F Cobolli | 6$^7$ | 1 | | | | | | | | | | |
| | A Vukic | 5 | 0$^r$ | | | | | | WC | A Pellegrino | 2 | 6 | 6 | | | | | |
| WC | G Zeppieri | 6 | 6 | | | | | | 4 | S Ofner | 6 | 2 | 3 | | | | | |
| WC | S Napolitano | 3 | 4 | | WC | G Zeppieri | 3 | 5 | | | | | | | | | | |
| Q | A Molčan | 7$^9$ | 0 | 3 | 4 | S Ofner | 6 | 7 | | | | | | | | | | |
| 4 | S Ofner | 6$^7$ | 6 | 6 | | | | | | | | | | WC | A Pellegrino | 3 | 6 | 6 |
| 7 | L Giustino | 7$^7$ | 7 | | | | | | | | | | | Q | V Kopřiva | 6 | 1 | 1 |
| | F Horanský | 6$^2$ | 5 | | 7 | L Giustino | 6 | 6 | | | | | | | | | | |
| | S Stakhovsky | 6 | 3 | 7 | | S Stakhovsky | 4 | 4 | | | | | | | | | | |
| SE | M Bourgue | 4 | 6 | 5 | | | | | 7 | L Giustino | 6 | 5 | 3 | | | | | |
| | B Tomic | 6 | 6 | | | | | | Q | V Kopřiva | 1 | 7 | 6 | | | | | |
| | R Bemelmans | 3 | 4 | | | B Tomic | 3 | 3 | | | | | | | | | | |
| Q | V Kopřiva | 7$^7$ | 6 | | Q | V Kopřiva | 6 | 6 | | | | | | | | | | |
| 2 | H Dellien | 6$^4$ | 3 | | | | | | | | | | | | | | | |