# 2021 ATP Lyon Open – Singles

Benoît Paire was the defending champion from when the event was last held in 2019, but chose to participate in Geneva instead.
Stefanos Tsitsipas won the title, defeating Cameron Norrie in the final 6–3, 6–3.

## Seeds

The top four seeds received a bye into the second round.
* Dominic Thiem (second round)
* Stefanos Tsitsipas (champion)
* Diego Schwartzman (second round)
* David Goffin (second round)
* Gaël Monfils (second round)
* Jannik Sinner (second round)
* Félix Auger-Aliassime (first round)
* Karen Khachanov (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 | Semifinals | Final | Final | Final | Final |
| | Cameron Norrie | 6 | 6 | | | | | |
| 8 | Karen Khachanov | 1 | 1 | | | | | |
| 8 | Karen Khachanov | 1 | 1 | | | Cameron Norrie | 3 | 3 |
| | | | | | 2/WC | Stefanos Tsitsipas | 6 | 6 |
| Alt | Lorenzo Musetti | 6 | 3 | 0 | 2/WC | Stefanos Tsitsipas | 6 | 6 |
| 2/WC | Stefanos Tsitsipas | 4 | 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 |
| | | | | | 1/WC | D Thiem | 3 | 2 | | | | | | | | | | |
| | C Moutet | 5 | 3 | | | C Norrie | 6 | 6 | | | | | | | | | | |
| | C Norrie | 7 | 6 | | | | | | | | C Norrie | 6 | 3 | 6 | | | | |
| LL | A Rinderknech | 6 | 6$^4$ | 6 | | | | | | LL | A Rinderknech | 3 | 6 | 3 | | | | |
| Q | M Ymer | 3 | 7$^7$ | 2 | LL | A Rinderknech | 6$^7$ | 6 | 7 | | | | | | | | | |
| | A Karatsev | 6 | 3 | 4 | 6 | J Sinner | 7$^9$ | 2 | 5 | | | | | | | | | |
| 6 | J Sinner | 0 | 6 | 6 | | | | | | | | | | | | C Norrie | 6 | 6 |
| | | | | | | | | | | | | | | | 8 | K Khachanov | 1 | 1 |
| | | | | | 3 | D Schwartzman | 3 | 5 | | | | | | | | | | |
| | R Gasquet | 5 | 6 | 6 | | R Gasquet | 6 | 7 | | | | | | | | | | |
| Q | G Barrère | 7 | 4 | 3 | | | | | | | R Gasquet | 1 | 6$^3$ | | | | | |
| Q | J Sousa | 3 | 6$^8$ | | | | | | | 8 | K Khachanov | 6 | 7$^7$ | | | | | |
| Q | K Majchrzak | 6 | 7$^{10}$ | | Q | K Majchrzak | 6$^4$ | 3 | | | | | | | | | | |
| WC | B Bonzi | 1 | 6 | 6$^4$ | 8 | K Khachanov | 7$^7$ | 6 | | | | | | | | | | |
| 8 | K Khachanov | 6 | 4 | 7$^7$ | | | | | | | | | | | | | | |

### 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 | Semifinals |
| 7 | F Auger-Aliassime | 6$^3$ | 6 | 5 | | | | | | | | | | | | | | |
| Alt | L Musetti | 7$^7$ | 3 | 7 | Alt | L Musetti | 6 | 1 | 6 | | | | | | | | | |
| | P-H Herbert | 6$^5$ | 4 | | | S Korda | 3 | 6 | 4 | | | | | | | | | |
| | S Korda | 7$^7$ | 6 | | | | | | | Alt | L Musetti | 6 | 7$^7$ | | | | | |
| | A Bedene | 6 | 6 | | | | | | | | A Bedene | 3 | 6$^2$ | | | | | |
| | G Simon | 2 | 3 | | | A Bedene | 7$^7$ | 6 | | | | | | | | | | |
| | | | | | 4 | D Goffin | 6$^4$ | 3 | | | | | | | | | | |
| | | | | | | | | | | | | | | Alt | L Musetti | 6 | 3 | 0 |
| 5 | G Monfils | 7 | 6 | | | | | | | | | | | 2/WC | S Tsitsipas | 4 | 6 | 6 |
| LL | T Seyboth Wild | 5 | 4 | | 5 | G Monfils | 6 | 3 | 6$^2$ | | | | | | | | | |
| | Y Nishioka | 3 | 6 | 6 | | Y Nishioka | 4 | 6 | 7$^7$ | | | | | | | | | |
| | U Humbert | 6 | 3 | 4 | | | | | | | Y Nishioka | 3 | 4 | | | | | |
| | T Paul | 6 | 6 | | | | | | | 2/WC | S Tsitsipas | 6 | 6 | | | | | |
| | J-W Tsonga | 3 | 3 | | | T Paul | 1 | 4 | | | | | | | | | | |
| | | | | | 2/WC | S Tsitsipas | 6 | 6 | | | | | | | | | | |

## Qualifying
### Seeds

* Lorenzo Musetti (moved to the main draw)
* Mikael Ymer (qualified)
* João Sousa (qualified)
* Grégoire Barrère (qualified)
* Arthur Rinderknech (qualifying competition, lucky loser)
* Thiago Seyboth Wild (qualifying competition, lucky loser)
* Kamil Majchrzak (qualified)
* Antoine Hoang (qualifying competition)

### Qualifiers

* Kamil Majchrzak
* Mikael Ymer
* João Sousa
* Grégoire Barrère

### Lucky losers

* Arthur Rinderknech
* Thiago Seyboth Wild

### Qualifying draw
#### First qualifier

| First round | First round | First round | First round | First round | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition |
| Alt | Peter Polansky | 3 | 4 | | | | | |
| | Alessandro Giannessi | 6 | 6 | | | | | |
| | Alessandro Giannessi | 6 | 6 | | | Alessandro Giannessi | 4 | 3 |
| | | | | | 7 | Kamil Majchrzak | 6 | 6 |
| | Liam Broady | 6 | 6$^2$ | 4 | 7 | Kamil Majchrzak | 6 | 6 |
| 7 | Kamil Majchrzak | 4 | 7$^7$ | 6 | | | | |

#### Second qualifier

| First round | First round | First round | First round | First round | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition |
| 2 | Mikael Ymer | 6 | 1 | 6 | | | | | |
| | Martin Kližan | 3 | 6 | 4 | | | | | |
| | Martin Kližan | 3 | 6 | 4 | 2 | Mikael Ymer | 6 | 4 | 6 |
| | | | | | 6 | Thiago Seyboth Wild | 4 | 6 | 1 |
| WC | Kyrian Jacquet | 1 | 4 | | 6 | Thiago Seyboth Wild | 4 | 6 | 1 |
| 6 | Thiago Seyboth Wild | 6 | 6 | | | | | | |

#### Third qualifier

| First round | First round | First round | First round | First round | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition |
| 3 | João Sousa | 6 | 6 | | | | | | |
| Alt | Roberto Marcora | 3 | 4 | | | | | | |
| Alt | Roberto Marcora | 3 | 4 | | 3 | João Sousa | 6 | 3 | 6 |
| | | | | | 5 | Arthur Rinderknech | 4 | 6 | 3 |
| Alt | Kimmer Coppejans | 5 | 6 | 6$^2$ | 5 | Arthur Rinderknech | 4 | 6 | 3 |
| 5 | Arthur Rinderknech | 7 | 3 | 7$^7$ | | | | | |

#### Fourth qualifier

| First round | First round | First round | First round | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition |
| 4 | Grégoire Barrère | 6 | 6 | | | | | |
| | Evgeny Donskoy | 2 | 3 | | | | | |
| | Evgeny Donskoy | 2 | 3 | 4 | Grégoire Barrère | 6 | 6$^5$ | 6 |
| | | | | 8 | Antoine Hoang | 3 | 7$^7$ | 1 |
| | Go Soeda | 1 | 1 | 8 | Antoine Hoang | 3 | 7$^7$ | 1 |
| 8 | Antoine Hoang | 6 | 6 | | | | | |