Stadium: Court 1N Round: 25 Ground: Hardcourt outdoor
| ITF M25 Koksijde | 2021/08/17 08:00 | Rojas, O. v Kotzen, Alexander | 6-4,6-3 |
| ITF M15 Gdynia | 2021/08/10 08:00 | Kotzen, Alexander v Olaf Pieczkowski | 2-6,6-2,8-10 |
| ITF M15 Gdynia | 2021/08/09 08:00 | Kotzen, Alexander v Pawlak, Piotr | 6-2,6-0 |
| ITF M15 Parnu | 2021/08/05 10:30 | Ergi Kirkin v Kotzen, Alexander | 7-6,6-4 |
| ITF M15 Parnu | 2021/08/04 09:05 | Tverijonas, Julius v Kotzen, Alexander | 6-3,5-7,2-6 |
| ITF M15 Vejle | 2021/07/30 08:00 | Ergi Kirkin v Kotzen, Alexander | 6-2,6-3 |
| ITF M15 Vejle | 2021/07/27 09:15 | Ruzgas, Marius v Kotzen, Alexander | 2-6,6-4,3-6 |
| ITF M15 Esch/Alzette | 2021/07/22 13:10 | Tommaso Compagnucci v Kotzen, Alexander | 6-2,6-0 |
| ITF M25 Decatur | 2021/08/02 15:00 | Horve, Lucas v Tristan Schoolkate | 0-6,6-4,7-10 |
| ITF M25 Champaign | 2021/07/28 16:45 | Horve, Lucas v Perez, Alfredo | 3-6,1-6 |
| ITF M25 Champaign | 2021/07/27 15:00 | Shane, Ryan v Horve, Lucas | 6-3,4-6,4-10 |
| ITF M25 Champaign | 2021/07/26 15:00 | Horve, Lucas v Smith, Errol | 3-6,6-2,10-6 |