Stadium: Court 4 Round: 26 Ground: Clay
| 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 |
| ITF M15 Troisdorf | 2021/05/12 09:00 | Schmitz, Constantin v Kocevar-Desman, Tom | 6-4,4-6,3-6 |
| ITF - M15 Antalya | 2021/04/14 10:30 | Ivan Sergeyev v Schmitz, Constantin | 6-3,5-7,6-3 |
| ITF - M15 Antalya | 2021/04/08 06:55 | Flavio Cobolli v Schmitz, Constantin | 7-6,7-6 |
| ITF - M15 Antalya | 2021/04/06 07:00 | Schmitz, Constantin v Bogdan Bobrov | 6-1,6-4 |
| ITF M15 Oldenzaal | 2021/08/18 15:15 | Romain Faucon v Johnson, Luke | 3-6,5-7 |
| ITF M15 Gdynia | 2021/08/11 14:25 | Johnson, Luke v Szymon Kielan | 1-6,6-7 |
| ITF M15 Gdynia | 2021/08/10 08:00 | Johnson, Luke v Harry Wendelken | 6-3,6-7,10-5 |
| ITF M15 Gdynia | 2021/08/09 08:00 | Johnson, Luke v Marcel Kamrowski | 6-3,6-2 |
| ITF M15 Parnu | 2021/08/06 08:00 | Ergi Kirkin v Johnson, Luke | 6-2,6-1 |
| ITF M15 Parnu | 2021/08/05 06:55 | Paul Valsecchi v Johnson, Luke | 6-3,4-6,0-6 |
| ITF M15 Parnu | 2021/08/04 12:05 | Lorenzo Rottoli v Johnson, Luke | 6-2,6-7,4-6 |
| Challenger Nottingham Qual | 2021/06/13 10:00 | Johnson, Luke v Ramkumar Ramanathan | 6-3,3-6,2-6 |