Stadium: Hard 21 Round: 25 Ground: Hardcourt outdoor
| ITF M15 Anif | 2020/08/26 14:40 | Karlis Ozolins v Kai Lemstra | 7-5,6-3 |
| ITF M15 Heraklion | 2021/11/03 07:00 | Karlis Ozolins v Aristotelis Thanos | 2-6,4-6 |
| ITF M15 Parnu | 2021/10/26 09:00 | Karlis Ozolins v Ainius Sabaliauskas | 5-7,4-6 |
| ITF M15 Champaign | 2021/09/15 14:55 | Karlis Ozolins v Dali Blanch | 5-7,6-7 |
| ITF M15 Zilina | 2021/09/01 09:55 | Karlis Ozolins v Francesco Vilardo | 1-6,2-6 |
| ITF M15 Bratislava | 2021/08/25 08:00 | Karlis Ozolins v Edoardo Lavagno | 0-6,6-0,4-6 |
| ITF M15 Lodz | 2021/08/17 08:00 | Karlis Ozolins v Markus Eriksson | 6-7,6-1,2-6 |
| ITF M25 Decatur | 2021/08/06 15:00 | Karlis Ozolins v Paul Jubb | 1-6,6-1,6-7 |
| ITF M25 Decatur | 2021/08/05 14:50 | Karlis Ozolins v Shintaro Imai | 7-6,3-6,7-6 |
| ITF M15 Heraklion | 2021/11/09 07:00 | Kai Lemstra v Christopher Patzanovsky | 6-2,6-4 |
| ITF M15 Heraklion | 2021/11/07 12:00 | Kai Lemstra v Drew Van Orderlain | 6-2,6-3 |
| ITF M15 Selva Gardena | 2021/10/27 08:00 | Kai Lemstra v Mattia Bellucci | 3-6,3-6 |
| ITF M15 Selva Gardena | 2021/10/26 07:30 | Kai Lemstra v Carlo Alberto Fossati | 6-4,7-5 |
| ITF M15 Selva Gardena | 2021/10/25 08:30 | Kai Lemstra v Dominique Graf | 7-5,6-2 |
| ITF M15 Selva Gardena | 2021/10/24 10:45 | Kai Lemstra v Davide Ferrarolli | 6-4,6-3 |
| ITF M25 Hamburg | 2021/10/17 07:55 | Tom Schonenberg v Kai Lemstra | 6-2,6-2 |
| ITF M15 Monastir | 2021/08/26 07:30 | Kai Lemstra v Renta Tokuda | 2-6,2-6 |