Stadium: Court 2 Round: 25 Ground: Clay
| Braunchsweig, Germany | 2021/07/10 09:00 | Daniel Altmaier v Marvin Moeller | 7-5,6-0 |
| Braunchsweig, Germany | 2021/07/08 13:00 | Marvin Moeller v Benjamin Hassan | 6-4,6-2 |
| Braunchsweig, Germany | 2021/07/07 09:30 | Sumit Nagal v Marvin Moeller | 3-6,6-1,2-6 |
| Braunchsweig, Germany | 2021/07/06 10:30 | Marvin Moeller v Gabashvili, Teimuraz | 7-5,6-3 |
| ITF M25 Wroclaw | 2021/06/28 09:30 | Marvin Moeller v Galik, Matej | 6-3,6-7,11-13 |
| ITF M25 Wroclaw | 2021/06/27 11:00 | Marvin Moeller v Jasza Szajrych | 6-2,6-1 |
| ITF M25 Alkmaar | 2021/06/25 11:30 | Nicolas Alvarez Varona v Marvin Moeller | 6-1,6-4 |
| ITF M25 Alkmaar | 2021/06/24 09:00 | Deney Wassermann v Marvin Moeller | 6-7,7-6,3-6 |
| 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 Antalya | 2021/05/06 08:10 | Nick Hardt v Peter Heller | 3-6,6-0,7-5 |
| ITF - M15 Antalya | 2021/05/05 08:55 | Karl Friberg v Peter Heller | 3-6,3-6 |
| ITF - M15 Antalya | 2021/05/01 07:30 | Peter Heller v Vanneste, Jeroen | 3-6,3-6 |
| ITF - M15 Antalya | 2021/04/30 09:50 | Rio Noguchi v Peter Heller | 6-2,3-6,2-6 |
| ITF - M15 Antalya | 2021/04/29 07:25 | Dan Alexandru Tomescu v Peter Heller | 6-0,3-6,5-7 |
| ITF - M15 Antalya | 2021/04/28 07:00 | Balzerani, Riccardo v Peter Heller | 1-6,4-6 |