| ITF M15 Troisdorf | 2021/05/12 09:00 | Constantin Schmitz v Tom Kocevar-Desman | 6-4,4-6,3-6 |
| ITF M15 Antalya | 2021/04/14 10:30 | Ivan Sergeyev v Constantin Schmitz | 6-3,5-7,6-3 |
| ITF M15 Antalya | 2021/04/08 06:55 | Flavio Cobolli v Constantin Schmitz | 7-6,7-6 |
| ITF M15 Antalya | 2021/04/06 07:00 | Constantin Schmitz v Bogdan Bobrov | 6-1,6-4 |
| ITF M15 Antalya | 2021/03/30 08:30 | Pol Martin Tiffon v Constantin Schmitz | 6-4,7-6 |
| ITF M15 Antalya | 2021/03/26 07:00 | Georgii Kravchenko v Constantin Schmitz | 6-2,6-3 |
| ITF M15 Antalya | 2021/03/24 07:30 | Constantin Schmitz v Pedro Vives Marcos | 6-3,6-3 |
| ITF M15 Monastir | 2021/03/10 10:30 | Yannick Mertens v Constantin Schmitz | 6-0,6-2 |
| 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 |
| ITF USA F25 | 2018/09/14 16:00 | Tim Sandkaulen v Robert Kelly | 6-7,6-1,6-0 |
| ITF Germany F9 | 2018/07/23 10:00 | Louroi Martinez v Tim Sandkaulen | 6-0,3-6,6-3 |
| ITF Germany F9 | 2018/07/22 11:00 | Tim Sandkaulen v Torben Steinorth | 6-4,6-1 |
| ITF Germany F9 | 2018/07/22 08:00 | Tim Sandkaulen v Lodewijk Weststrate | 6-2,7-6 |
| Challenger Meerbusch Qual | 2017/08/12 12:10 | Antonio Sancic v Tim Sandkaulen | 7-6,6-1 |