# 2021 Heilbronner Neckarcup – Singles

Filip Krajinović was the defending champion but chose not to defend his title.
Bernabé Zapata Miralles won the title after defeating Daniel Elahi Galán 6–3, 6–4 in the final.

## Seeds

* Jiří Veselý (first round)
* Yannick Hanfmann (second round)
* Dennis Novak (semifinals)
* Daniel Elahi Galán (final)
* Taro Daniel (quarterfinals)
* Denis Kudla (first round)
* Philipp Kohlschreiber (quarterfinals)
* Mackenzie McDonald (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 |
| | Bernabé Zapata Miralles | 6 | 1 | 6 | | | | |
| 3 | Dennis Novak | 3 | 6 | 3 | | | | |
| 3 | Dennis Novak | 3 | 6 | 3 | | Bernabé Zapata Miralles | 6 | 6 |
| | | | | | 4 | Daniel Elahi Galán | 3 | 4 |
| 4 | Daniel Elahi Galán | 6 | 6$^4$ | 7 | 4 | Daniel Elahi Galán | 3 | 4 |
| 8 | Mackenzie McDonald | 4 | 7$^7$ | 5 | | | | |

### 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 | Semifinals |
| 1 | J Veselý | 6$^2$ | 6$^3$ | | | | | | | | | | | | | | | |
| | O Otte | 7$^7$ | 7$^7$ | | | O Otte | 2 | 1 | | | | | | | | | | |
| | I Marchenko | 3 | 6$^2$ | | | B Zapata Miralles | 6 | 6 | | | | | | | | | | |
| | B Zapata Miralles | 6 | 7$^7$ | | | | | | | | B Zapata Miralles | 6 | 6 | | | | | |
| WC | R Molleker | 0 | 6 | 3 | | | | | | | S Nagal | 3 | 1 | | | | | |
| | A Hoang | 6 | 3 | 6 | | A Hoang | 6 | 1 | 4 | | | | | | | | | |
| | S Nagal | 7 | 1 | 6 | | S Nagal | 1 | 6 | 6 | | | | | | | | | |
| 6 | D Kudla | 5 | 6 | 1 | | | | | | | | | | | B Zapata Miralles | 6 | 1 | 6 |
| 3 | D Novak | 6 | 2 | 7 | | | | | | | | | | 3 | D Novak | 3 | 6 | 3 |
| WC | Y Maden | 2 | 6 | 5 | 3 | D Novak | 7$^7$ | 4 | 7 | | | | | | | | | |
| Q | M Moraing | 7$^7$ | 6 | | Q | M Moraing | 6$^4$ | 6 | 5 | | | | | | | | | |
| | H Laaksonen | 6$^2$ | 2 | | | | | | | 3 | D Novak | 6 | 6 | | | | | |
| LL | TM Etcheverry | 6 | 6 | | | | | | | 5 | T Daniel | 4 | 4 | | | | | |
| PR | A Kuznetsov | 3 | 2 | | LL | TM Etcheverry | 4 | 1 | | | | | | | | | | |
| | D Altmaier | 5 | 0 | | 5 | T Daniel | 6 | 6 | | | | | | | | | | |
| 5 | T Daniel | 7 | 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 | P Kohlschreiber | 6 | 6 | | | | | | | | | | | | | | | | |
| Q | M Janvier | 4 | 3 | | 7 | P Kohlschreiber | 3 | 6 | 6 | | | | | | | | | | |
| | M-A Hüsler | 7$^7$ | 4 | 6$^3$ | | B Nakashima | 6 | 4 | 1 | | | | | | | | | | |
| | B Nakashima | 6$^3$ | 6 | 7$^7$ | | | | | | 7 | P Kohlschreiber | 6 | 2 | 6$^4$ | | | | | |
| Alt | A Giannessi | 7$^7$ | 6 | | | | | | | 4 | DE Galán | 2 | 6 | 7$^7$ | | | | | |
| | P Gunneswaran | 6$^4$ | 1 | | Alt | A Giannessi | 7$^7$ | 6$^7$ | 4 | | | | | | | | | | |
| | M Polmans | 1 | 1 | | 4 | DE Galán | 6$^4$ | 7$^9$ | 6 | | | | | | | | | | |
| 4 | DE Galán | 6 | 6 | | | | | | | | | | | | 4 | DE Galán | 6 | 6$^4$ | 7 |
| 8 | M McDonald | 6 | 4 | | | | | | | | | | | | 8 | M McDonald | 4 | 7$^7$ | 5 |
| Q | A Vukic | 3 | 3$^r$ | | 8 | M McDonald | 6 | 4 | 6 | | | | | | | | | | |
| Alt | K Coppejans | 6 | 6 | | Alt | K Coppejans | 4 | 6 | 3 | | | | | | | | | | |
| | C Taberner | 2 | 1 | | | | | | | 8 | M McDonald | 6 | 6 | | | | | | |
| Q | E Kırkın | 6$^6$ | 6 | 5 | | | | | | LL | J Menezes | 3 | 3 | | | | | | |
| LL | J Menezes | 7$^8$ | 2 | 7 | LL | J Menezes | 6 | 6 | | | | | | | | | | | |
| | T Griekspoor | 0 | 4 | | 2/WC | Y Hanfmann | 4 | 3 | | | | | | | | | | | |
| 2/WC | Y Hanfmann | 6 | 6 | | | | | | | | | | | | | | | | |