# 2021 Meerbusch Challenger – Singles

Pedro Sousa was the defending champion but chose not to defend his title.
Marcelo Tomás Barrios Vera won the title after defeating Juan Manuel Cerúndolo 7–6$^{(9–7)}$, 6–3 in the final.

## Seeds

* Daniel Altmaier (quarterfinals)
* Damir Džumhur (second round)
* Botic van de Zandschulp (semifinals)
* Oscar Otte (second round)
* Juan Manuel Cerúndolo (final)
* Tomáš Macháč (first round)
* Alex Molčan (withdrew)
* Sumit Nagal (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 |
| | Marcelo Tomás Barrios Vera | 6 | 4 | 6 | | | | |
| | Robin Haase | 3 | 6 | 2 | | | | |
| | Robin Haase | 3 | 6 | 2 | | Marcelo Tomás Barrios Vera | 7$^9$ | 6 |
| | | | | | 5 | Juan Manuel Cerúndolo | 6$^7$ | 3 |
| 3 | Botic van de Zandschulp | 5 | 4 | | 5 | Juan Manuel Cerúndolo | 6$^7$ | 3 |
| 5 | Juan Manuel Cerúndolo | 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 | D Altmaier | 6 | 7 | | | | | | | | | | | | | | | |
| | A Tabilo | 0 | 5 | | 1 | D Altmaier | 7$^7$ | 3 | 6 | | | | | | | | | |
| | V Kopřiva | 7 | 6 | | | V Kopřiva | 6$^3$ | 6 | 3 | | | | | | | | | |
| LL | N Fatić | 5 | 2 | | | | | | | 1 | D Altmaier | 4 | 6 | 6$^4$ | | | | |
| | N Kuhn | 6 | 6 | | | | | | | | MT Barrios Vera | 6 | 1 | 7$^7$ | | | | |
| Q | N Hardt | 4 | 3 | | | N Kuhn | | | | | | | | | | | | |
| | MT Barrios Vera | 7 | 4 | 6 | | MT Barrios Vera | w/o | | | | | | | | | | | |
| 8 | S Nagal | 5 | 6 | 3 | | | | | | | | | | | MT Barrios Vera | 6 | 4 | 6 |
| 4 | O Otte | 6 | 6 | | | | | | | | | | | | R Haase | 3 | 6 | 2 |
| WC | M Rosenkranz | 4 | 4 | | 4 | O Otte | 6 | 5 | 3 | | | | | | | | | |
| Q | J de Jong | 3 | 7$^7$ | 4 | | R Haase | 3 | 7 | 6 | | | | | | | | | |
| | R Haase | 6 | 6$^5$ | 6 | | | | | | | R Haase | 4 | 6 | 6 | | | | |
| Q | N Kicker | 6 | 6 | | | | | | | | M Moraing | 6 | 3 | 3 | | | | |
| | JP Ficovich | 4 | 3 | | Q | N Kicker | 4 | 2 | | | | | | | | | | |
| | M Moraing | 7$^7$ | 6 | | | M Moraing | 6 | 6 | | | | | | | | | | |
| 6 | T Macháč | 6$^0$ | 3 | | | | | | | | | | | | | | | |

### 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 |
| Q | D Ajduković | 6 | 6$^3$ | 7 | | | | | | | | | | | | | | |
| WC | S Mochizuki | 3 | 7$^7$ | 5 | Q | D Ajduković | 4 | 6 | 4 | | | | | | | | | |
| | L Klein | 6 | 6 | | | L Klein | 6 | 4 | 6 | | | | | | | | | |
| | T Kamke | 1 | 2 | | | | | | | | L Klein | 4 | 6 | 4 | | | | |
| | R Safiullin | 4 | 7$^7$ | 4 | | | | | | 3 | B van de Zandschulp | 6 | 3 | 6 | | | | |
| | C Lestienne | 6 | 6$^3$ | 6 | | C Lestienne | 4 | 6 | 4 | | | | | | | | | |
| | R Cid Subervi | 6 | 4 | 6$^4$ | 3 | B van de Zandschulp | 6 | 3 | 6 | | | | | | | | | |
| 3 | B van de Zandschulp | 3 | 6 | 7$^7$ | | | | | | | | | | | 3 | B van de Zandschulp | 5 | 4 |
| 5 | JM Cerúndolo | 2 | 6 | 6 | | | | | | | | | | | 5 | JM Cerúndolo | 7 | 6 |
| | K Coppejans | 6 | 2 | 2 | 5 | JM Cerúndolo | 6 | 7$^7$ | | | | | | | | | | |
| WC | R Molleker | 6 | 3 | 2 | | M Marterer | 4 | 6$^3$ | | | | | | | | | | |
| | M Marterer | 3 | 6 | 6 | | | | | | 5 | JM Cerúndolo | 3 | 6 | 7 | | | | |
| | F Horanský | 6 | 6 | | | | | | | | F Horanský | 6 | 1 | 5 | | | | |
| | A Collarini | 4 | 2 | | | F Horanský | 7$^7$ | 2 | 6 | | | | | | | | | |
| | R Bemelmans | 3 | 3 | | 2 | D Džumhur | 6$^4$ | 6 | 2 | | | | | | | | | |
| 2 | D Džumhur | 6 | 6 | | | | | | | | | | | | | | | |