Stadium: Court 5 Round: 62 Ground: Clay
| ITF Austria F3 | 2017/07/16 11:25 | Edward Hubner v Kai Lemstra | 1-6,3-6 |
| ITF M25 Most | 2021/05/24 08:00 | Kai Lemstra v Niklas Rohrer | 6-3,6-2 |
| ITF M25 Most | 2021/05/23 14:00 | Kai Lemstra v Vojtech Petr | 6-4,6-4 |
| ITF M25 Jablonec Nad Nisou | 2021/05/18 07:30 | Andrew Paulson v Kai Lemstra | 6-3,6-4 |
| ITF M25 Jablonec Nad Nisou | 2021/05/17 07:30 | Jan Jermar v Kai Lemstra | 4-6,4-6 |
| ITF M25 Jablonec Nad Nisou | 2021/05/16 08:30 | Matyas Cerny v Kai Lemstra | 3-6,3-6 |
| ITF M25 Meerbusch | 2021/04/12 09:30 | Marvin Netuschil v Kai Lemstra | 6-2,6-3 |
| ITF M15 Monastir | 2021/03/15 12:30 | Kai Lemstra v Alexander Kotzen | 1-6,3-6 |
| ITF M15 Monastir | 2021/03/15 08:00 | Kai Lemstra v John Sperle | 6-3,6-3 |
| ITF M25 Most | 2021/05/24 09:00 | Niklas Waldner v Edward Hubner | 4-6,3-6 |
| ITF M25 Most | 2021/05/23 14:00 | Martin Benes v Edward Hubner | 4-6,4-6 |
| ITF M15 Antalya | 2021/04/11 07:00 | Daniil Gusev v Edward Hubner | 4-6,7-6,5-10 |
| ITF M15 Antalya | 2021/04/06 07:00 | Michel Vernier v Edward Hubner | 5-7,6-0,12-10 |
| ITF M15 Antalya | 2021/04/05 07:00 | Edward Hubner v Taiyo Yamanaka | 6-7,6-2,10-5 |
| ITF M15 Antalya | 2021/04/04 06:30 | Edward Hubner v Daniil Savelev | 6-1,6-1 |
| ITF M15 Antalya | 2021/03/28 06:30 | Edward Hubner v Alexis Boureau | 7-5,6-3 |
| ITF M15 Bratislava | 2021/03/10 09:00 | Edward Hubner v Peter Fajta | 7-6,4-6,2-6 |