Stadium: Court 09 Round: 26 Ground: Clay
| ITF M15 Warmbad-Villach | 2021/08/18 08:00 | Peter Heller v Andrea Guerrieri | 6-1,6-1 |
| ITF M25 Wetzlar | 2021/08/08 10:00 | Peter Heller v Christopher Heyman | 6-4,6-7,6-4 |
| ITF M25 Wetzlar | 2021/08/07 11:00 | David Pichler v Peter Heller | 3-6,7-5,3-6 |
| ITF M25 Wetzlar | 2021/08/06 15:55 | Constantin Schmitz v Peter Heller | 3-6,7-5,1-6 |
| ITF M25 Wetzlar | 2021/08/05 09:00 | Georgii Kravchenko v Peter Heller | 6-7,2-6 |
| ITF M25 Wetzlar | 2021/08/04 08:00 | Marvin Moeller v Peter Heller | 2-6,3-6 |
| Challenger Salzburg | 2021/07/08 10:30 | Nicolas Jarry v Peter Heller | 6-2,6-4 |
| Challenger Salzburg | 2021/07/05 10:35 | Francisco Cerundolo v Peter Heller | 3-6,6-3,3-6 |
| ITF M15 Warmbad-Villach | 2021/08/17 14:15 | Bjorn Nareyka v Maximilian Homberg | 1-6,2-6 |
| ITF M25 Marburg | 2021/07/05 08:00 | Guy Den Heijer v Maximilian Homberg | 6-7,6-2,10-8 |