| ITF M15 Allershausen | 2021/08/31 11:25 | Schmitz, Constantin v Veldheer, Mick | 6-7,4-6 |
| ITF M25 Trier | 2021/08/26 09:30 | Schmitz, Constantin v Ryan Nijboer | 4-6,2-6 |
| ITF M25 Trier | 2021/08/25 11:40 | Mats Rosenkranz v Schmitz, Constantin | 1-6,1-6 |
| ITF M15 Oldenzaal | 2021/08/19 12:35 | Schmitz, Constantin v Johnson, Luke | 7-5,0-6,3-6 |
| ITF M15 Oldenzaal | 2021/08/18 14:10 | Schmitz, Constantin v Eisinga, Zachary | 6-3,7-6 |
| ITF M25 Wetzlar | 2021/08/06 15:55 | Schmitz, Constantin v Peter Heller | 3-6,7-5,1-6 |
| ITF M25 Wetzlar | 2021/08/05 13:55 | Kelly, Dayne v Schmitz, Constantin | 2-6,1-6 |
| ITF M25 Wetzlar | 2021/08/04 12:30 | Schmitz, Constantin v Rother, Jannik | 6-2,6-0 |
| UTR Pro Tennis Series Mulheim | 2021/07/31 08:30 | Hazem Naw v Sandkaulen, Tim | 6-4,7-6 |
| UTR Pro Tennis Series Mulheim | 2021/07/29 13:30 | Matthew Thomson v Sandkaulen, Tim | 6-7,1-6 |
| UTR Pro Tennis Series Mulheim | 2021/07/29 07:00 | Billy Harris v Sandkaulen, Tim | 6-7,3-6 |
| UTR Pro Tennis Series Mulheim | 2021/07/28 11:00 | Mark Wallner v Sandkaulen, Tim | 6-7,5-6 |
| UTR Pro Tennis Series Mulheim | 2021/07/26 11:00 | Guy Den Heijer v Sandkaulen, Tim | 7-5,6-3 |
| Braunchsweig, Germany | 2021/07/05 09:30 | Sandkaulen, Tim v Daniel Michalski | 3-6,5-7 |
| Braunchsweig, Germany | 2021/07/04 09:00 | Kacper Zuk v Sandkaulen, Tim | 6-2,3-6,6-7 |
| ITF USA F25 | 2018/09/15 17:30 | Kohen, Alan v Sandkaulen, Tim | 6-4,6-4 |