# 2021 Wolffkran Open – Singles

Marc-Andrea Hüsler was the defending champion but lost in the first round to Mats Rosenkranz.
Oscar Otte won the title after defeating Lukáš Lacko 6–4, 6–4 in the final.

## Seeds

* Jordan Thompson (first round)
* Jiří Veselý (first round)
* Andreas Seppi (second round)
* Yannick Hanfmann (first round)
* Oscar Otte (champion)
* Tomáš Macháč (second round)
* Maxime Cressy (semifinals)
* Quentin Halys (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 |
| 8 | Quentin Halys | 1 | 6$^5$ | | | | | |
| | Lukáš Lacko | 6 | 7$^7$ | | | | | |
| | Lukáš Lacko | 6 | 7$^7$ | | | Lukáš Lacko | 4 | 4 |
| | | | | | 5 | Oscar Otte | 6 | 6 |
| 7 | Maxime Cressy | 5 | 6 | 6$^5$ | 5 | Oscar Otte | 6 | 6 |
| 5 | Oscar Otte | 7 | 2 | 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 | Quarterfinals | Semifinals | Semifinals | Semifinals | Semifinals |
| 1 | J Thompson | 7 | 2 | 2 | | | | | | | | | | | | | | |
| Q | J Forejtek | 5 | 6 | 6 | Q | J Forejtek | 7$^7$ | 3 | 6 | | | | | | | | | |
| | M Moraing | | | | PR | Y Maden | 6$^3$ | 6 | 1 | | | | | | | | | |
| PR | Y Maden | w/o | | | | | | | | Q | J Forejtek | 6 | 2 | 2 | | | | |
| WC | H Squire | 3 | 4 | | | | | | | 8 | Q Halys | 3 | 6 | 6 | | | | |
| | R Bemelmans | 6 | 6 | | | R Bemelmans | 6$^8$ | 7$^7$ | 4 | | | | | | | | | |
| | D Masur | 4 | 7 | 3 | 8 | Q Halys | 7$^{10}$ | 6$^5$ | 6 | | | | | | | | | |
| 8 | Q Halys | 6 | 5 | 6 | | | | | | | | | | | 8 | Q Halys | 1 | 6$^5$ |
| 4 | Y Hanfmann | 7 | 6$^4$ | 4 | | | | | | | | | | | | L Lacko | 6 | 7$^7$ |
| | T van Rijthoven | 5 | 7$^7$ | 6 | | T van Rijthoven | 7$^7$ | 4 | 2 | | | | | | | | | |
| | A Çelikbilek | 3 | 1 | | Q | M Bachinger | 6$^4$ | 6 | 6 | | | | | | | | | |
| Q | M Bachinger | 6 | 6 | | | | | | | Q | M Bachinger | 5 | 6 | 4 | | | | |
| | M Copil | 6$^8$ | 6$^4$ | | | | | | | | L Lacko | 7 | 3 | 6 | | | | |
| | L Lacko | 7$^{10}$ | 7$^7$ | | | L Lacko | 6$^2$ | 6 | 7$^7$ | | | | | | | | | |
| | K Coppejans | 4 | 2 | | 6 | T Macháč | 7$^7$ | 4 | 6$^2$ | | | | | | | | | |
| 6 | T Macháč | 6 | 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 | Semifinals |
| 7 | M Cressy | 6 | 7 | | | | | | | | | | | | | | | | |
| LL | H Moriya | 3 | 5 | | 7 | M Cressy | 7$^7$ | 3 | 7 | | | | | | | | | | |
| Q | O Virtanen | 7 | 6 | | Q | O Virtanen | 6$^5$ | 6 | 5 | | | | | | | | | | |
| WC | MH Rehberg | 5 | 2 | | | | | | | 7 | M Cressy | 6$^7$ | 6 | 7$^7$ | | | | | |
| Alt | V Sachko | 2 | 4 | | | | | | | | K Żuk | 7$^9$ | 4 | 6$^4$ | | | | | |
| | K Żuk | 6 | 6 | | | K Żuk | 4 | 6 | 7$^7$ | | | | | | | | | | |
| Alt | T Kamke | 5 | 3 | | 3 | A Seppi | 6 | 4 | 6$^4$ | | | | | | | | | | |
| 3 | A Seppi | 7 | 6 | | | | | | | | | | | | 7 | M Cressy | 5 | 6 | 6$^5$ |
| 5 | O Otte | 6$^4$ | 6 | 6 | | | | | | | | | | | 5 | O Otte | 7 | 2 | 7$^7$ |
| | R Haase | 7$^7$ | 4 | 4 | 5 | O Otte | 6 | 6 | | | | | | | | | | | |
| | C İlkel | 7$^7$ | 5 | 1 | Q | J Lenz | 3 | 4 | | | | | | | | | | | |
| Q | J Lenz | 6$^5$ | 7 | 6 | | | | | | 5 | O Otte | 3 | 6 | 7$^7$ | | | | | |
| | M-A Hüsler | 7$^7$ | 2 | 6$^0$ | | | | | | | M Marterer | 6 | 3 | 6$^5$ | | | | | |
| WC | M Rosenkranz | 6$^2$ | 6 | 7$^7$ | WC | M Rosenkranz | 3 | 6$^3$ | | | | | | | | | | | |
| | M Marterer | 7$^{10}$ | 6 | | | M Marterer | 6 | 7$^7$ | | | | | | | | | | | |
| 2 | J Veselý | 6$^8$ | 4 | | | | | | | | | | | | | | | | |