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