# 2021 Hamburg European Open – Men's singles

Andrey Rublev was the defending champion, but chose to not defend his title as he and other Russian Olympic athletes were sent to Yuzhno-Sakhalinsk for training sessions.
Pablo Carreño Busta won his maiden ATP Tour 500 singles title, defeating Filip Krajinović in the final, 6–2, 6–4.

## Seeds

The top four seeds received a bye into the second round.
* Stefanos Tsitsipas (quarterfinals)
* Pablo Carreño Busta (champion)
* Nikoloz Basilashvili (quarterfinals)
* Albert Ramos Viñolas (second round)
* Dušan Lajović (quarterfinals)
* Filip Krajinović (final)
* Jan-Lennard Struff (first round)
* Benoît Paire (quarterfinals)

## 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 |
| 6 | Filip Krajinović | 6 | 6 | | | | |
| | Laslo Đere | 4 | 2 | | | | |
| | Laslo Đere | 4 | 2 | 6 | Filip Krajinović | 2 | 4 |
| | | | | 2 | Pablo Carreño Busta | 6 | 6 |
| | Federico Delbonis | 6$^2$ | 3 | 2 | Pablo Carreño Busta | 6 | 6 |
| 2 | Pablo Carreño Busta | 7$^7$ | 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 | S Tsitsipas | 7$^7$ | 6 | | | | | | | | | | |
| Q | M Marterer | 6$^2$ | 6 | 6$^4$ | | D Koepfer | 6$^2$ | 3 | | | | | | | | | | |
| | D Koepfer | 7$^7$ | 2 | 7$^7$ | | | | | | 1/WC | S Tsitsipas | 6 | 1 | 3 | | | | |
| | J Munar | 6$^5$ | 4 | | | | | | | 6 | F Krajinović | 3 | 6 | 6 | | | | |
| WC | P Kohlschreiber | 7$^7$ | 6 | | WC | P Kohlschreiber | 5 | 6 | 3 | | | | | | | | | |
| WC | D Altmaier | 3 | 7$^7$ | 1 | 6 | F Krajinović | 7 | 4 | 6 | | | | | | | | | |
| 6 | F Krajinović | 6 | 6$^3$ | 6 | | | | | | | | | | | 6 | F Krajinović | 6 | 6 |
| | | | | | | | | | | | | | | | | L Đere | 4 | 2 |
| | | | | | 3 | N Basilashvili | w/o | | | | | | | | | | | |
| | C Moutet | 1 | 2 | | LL | S Báez | | | | | | | | | | | | |
| LL | S Báez | 6 | 6 | | | | | | | 3 | N Basilashvili | 2 | 2 | | | | | |
| WC | N Kuhn | 6 | 1 | 2 | | | | | | | L Đere | 6 | 6 | | | | | |
| Q | T Seyboth Wild | 1 | 6 | 6 | Q | T Seyboth Wild | 6$^1$ | 1 | | | | | | | | | | |
| | L Đere | 6 | 7 | | | L Đere | 7$^7$ | 6 | | | | | | | | | | |
| 7 | J-L Struff | 4 | 5 | | | | | | | | | | | | | | | |

### 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 |
| 8 | B Paire | 6 | | | | | | | | | | | | | | | | |
| | R Berankis | 6$^r$ | | | 8 | B Paire | 7 | 7$^{10}$ | | | | | | | | | | |
| Q | JP Varillas | 6 | 6 | | Q | JP Varillas | 5 | 6$^8$ | | | | | | | | | | |
| LL | S Nagal | 0 | 4 | | | | | | | 8 | B Paire | 6 | 6$^9$ | 4 | | | | |
| | F Delbonis | 6 | 5 | 6 | | | | | | | F Delbonis | 4 | 7$^{11}$ | 6 | | | | |
| Q | Zh Zhang | 1 | 7 | 4 | | F Delbonis | 6 | 7$^7$ | | | | | | | | | | |
| | | | | | 4 | A Ramos Viñolas | 3 | 6$^4$ | | | | | | | | | | |
| | | | | | | | | | | | | | | | | F Delbonis | 6$^2$ | 3 |
| 5 | D Lajović | 6 | 6 | | | | | | | | | | | | 2 | P Carreño Busta | 7$^7$ | 6 |
| | L Pouille | 4 | 4 | | 5 | D Lajović | 6 | 6$^2$ | 6 | | | | | | | | | |
| | G Mager | 6 | 4 | 6$^3$ | Q | A Molčan | 4 | 7$^7$ | 3 | | | | | | | | | |
| Q | A Molčan | 4 | 6 | 7$^7$ | | | | | | 5 | D Lajović | 6$^4$ | 3 | | | | | |
| Q | C Taberner | 6 | 3 | 6 | | | | | | 2 | P Carreño Busta | 7$^7$ | 6 | | | | | |
| | F López | 4 | 6 | 3 | Q | C Taberner | 5 | 3 | | | | | | | | | | |
| | | | | | 2 | P Carreño Busta | 7 | 6 | | | | | | | | | | |

## Qualifying
### Seeds

* Carlos Taberner (qualified)
* Thiago Seyboth Wild (qualified)
* Jozef Kovalík (first round)
* Damir Džumhur (first round)
* Christopher O'Connell (qualifying competition)
* Juan Pablo Varillas (qualified)
* Sumit Nagal (qualifying competition; Lucky loser)
* Oscar Otte (first round)
* Alex Molčan (qualified)
* Sebastián Báez (qualifying competition; Lucky loser)
* Alessandro Giannessi (qualifying competition)
* Danilo Petrović (first round)

### Qualifiers

* Carlos Taberner
* Thiago Seyboth Wild
* Zhang Zhizhen
* Maximilian Marterer
* Alex Molčan
* Juan Pablo Varillas

### Lucky losers

* Sumit Nagal
* Sebastián Báez

### Qualifying draw
#### First qualifier

| First round | First round | First round | First round | First round | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition |
| 1 | Carlos Taberner | 6 | 6 | | | | | | |
| WC | Niklas Guttau | 1 | 2 | | | | | | |
| WC | Niklas Guttau | 1 | 2 | | 1 | Carlos Taberner | 2 | 7$^7$ | 6 |
| | | | | | | Daniel Masur | 6 | 6$^5$ | 4 |
| | Daniel Masur | 2 | 6 | 6 | | Daniel Masur | 6 | 6$^5$ | 4 |
| 12 | Danilo Petrović | 6 | 4 | 3 | | | | | |

#### Second qualifier

| First round | First round | First round | First round | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition |
| 2 | Thiago Seyboth Wild | 6 | 6 | | | | |
| WC | Mats Rosenkranz | 3 | 1 | | | | |
| WC | Mats Rosenkranz | 3 | 1 | 2 | Thiago Seyboth Wild | 6 | 7 |
| | | | | | Steven Diez | 3 | 5 |
| | Steven Diez | 6 | 6 | | Steven Diez | 3 | 5 |
| 8 | Oscar Otte | 4 | 4 | | | | |

#### Third qualifier

| First round | First round | First round | First round | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition |
| 3 | Jozef Kovalík | 4 | 4 | | | | |
| | Zhang Zhizhen | 6 | 6 | | | | |
| | Zhang Zhizhen | 6 | 6 | | Zhang Zhizhen | 6 | 6 |
| | | | | 7 | Sumit Nagal | 4 | 2 |
| WC | Lewie Lane | 3 | 1 | 7 | Sumit Nagal | 4 | 2 |
| 7 | Sumit Nagal | 6 | 6 | | | | |

#### Fourth qualifier

| First round | First round | First round | First round | First round | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition |
| 4 | Damir Džumhur | 7 | 2 | 3 | | | | | |
| | Maximilian Marterer | 5 | 6 | 6 | | | | | |
| | Maximilian Marterer | 5 | 6 | 6 | | Maximilian Marterer | 3 | 6 | 7 |
| | | | | | 11 | Alessandro Giannessi | 6 | 3 | 5 |
| | Tobias Kamke | 3 | 4 | | 11 | Alessandro Giannessi | 6 | 3 | 5 |
| 11 | Alessandro Giannessi | 6 | 6 | | | | | | |

#### Fifth qualifier

| First round | First round | First round | First round | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition |
| 5 | Christopher O'Connell | 6 | 6 | | | | | |
| | Ernests Gulbis | 3 | 0 | | | | | |
| | Ernests Gulbis | 3 | 0 | 5 | Christopher O'Connell | 3 | 7 | 3 |
| | | | | 9 | Alex Molčan | 6 | 5 | 6 |
| | Filip Horanský | 6$^5$ | 2 | 9 | Alex Molčan | 6 | 5 | 6 |
| 9 | Alex Molčan | 7$^7$ | 6 | | | | | |

#### Sixth qualifier

| First round | First round | First round | First round | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition |
| 6 | Juan Pablo Varillas | 7 | 6 | | | | | |
| | Jonáš Forejtek | 5 | 2 | | | | | |
| | Jonáš Forejtek | 5 | 2 | 6 | Juan Pablo Varillas | 6 | 3 | 7$^7$ |
| | | | | 10 | Sebastián Báez | 2 | 6 | 6$^0$ |
| | Rudolf Molleker | 5 | 2 | 10 | Sebastián Báez | 2 | 6 | 6$^0$ |
| 10 | Sebastián Báez | 7 | 6 | | | | | |