Stadium: Court 1 Round: 26 Ground: Hardcourt indoor
| ITF M15 - Vejle | 2021/07/30 08:00 | Ergi Kirkin v Alexander Kotzen | 6-2,6-3 |
| ITF M15 - Pärnu | 2021/08/04 08:35 | Ergi Kirkin v Oscar Weightman | 6-2,4-6,7-5 |
| ITF M15 - Vejle | 2021/08/01 10:20 | Ergi Kirkin v August Holmgren | 7-6,6-4 |
| ITF M15 - Vejle | 2021/07/31 07:50 | Ergi Kirkin v Matias Zukas | 6-1,6-4 |
| ITF M15 - Vejle | 2021/07/30 13:00 | Ergi Kirkin v Karl Friberg | 6-3,6-0 |
| ITF M15 - Vejle | 2021/07/30 08:00 | Ergi Kirkin v Alexander Kotzen | 6-2,6-3 |
| ITF M15 - Vejle | 2021/07/28 10:25 | Ergi Kirkin v Andrea Del Federico | 3-6,6-2,6-2 |
| Challenger - Nur-Sultan | 2021/07/20 09:10 | Ergi Kirkin v Ryan Peniston | 2-6,3-6 |
| Challenger - Nur-Sultan | 2021/07/19 06:10 | Ergi Kirkin v Benjamin Lock | 5-7,7-6,3-6 |
| ITF M15 - Pärnu | 2021/08/04 09:05 | Julius Tverijonas v Alexander Kotzen | 6-3,5-7,2-6 |
| ITF M15 - Vejle | 2021/07/30 08:00 | Ergi Kirkin v Alexander Kotzen | 6-2,6-3 |
| ITF M15 - Vejle | 2021/07/27 09:15 | Marius Ruzgas v Alexander Kotzen | 2-6,6-4,3-6 |
| ITF M15 - Esch/Alzette | 2021/07/22 13:10 | Tommaso Compagnucci v Alexander Kotzen | 6-2,6-0 |
| ITF M15 - Esch/Alzette | 2021/07/21 10:55 | Alexander Kotzen v Louis Wessels | 2-6,6-3,6-4 |
| ITF M15 - Esch/Alzette | 2021/07/20 11:00 | Benjamin Dhoe v Alexander Kotzen | 3-6,4-6 |
| ITF M15 - Esch/Alzette | 2021/07/19 09:00 | Alexander Kotzen v Tibo Colson | 4-6,6-1,10-7 |
| ITF M15 - Esch/Alzette | 2021/07/18 07:55 | Alexander Kotzen v Victor Ernaelsteen | 6-1,6-4 |