Stadium: Court 2 Round: 62 Ground: Hardcourt outdoor
| ITF M25 Wetzlar | 2021/08/02 14:00 | Osman Torski v Kai Lemstra | 6-4,0-6,10-5 |
| ITF M25 Most | 2021/05/26 10:15 | Antoine Escoffier v Kai Lemstra | 6-3,7-5 |
| ITF M25 Most | 2021/05/25 10:15 | Kai Lemstra v Edward Hubner | 6-1,6-1 |
| 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 M15 Monastir | 2021/08/15 07:30 | Joshua Sheehy v Blake Ellis | 5-7,4-6 |
| ITF M15 Monastir | 2021/08/10 07:30 | Kyle Seelig v Blake Ellis | 6-4,6-4 |
| ITF M15 Monastir | 2021/08/02 07:30 | Blake Ellis v Jan Sebesta | 3-6,6-4,3-10 |
| UTR Pro Tennis Series Brisbane | 2021/07/25 04:00 | Blake Ellis v Scott Jones | 7-6,6-7,5-4 |
| UTR Pro Tennis Series Brisbane | 2021/07/24 07:00 | Blake Ellis v Moerani Bouzige | 6-7,7-6,7-6 |
| UTR Pro Tennis Series Brisbane | 2021/07/23 22:30 | Tom Evans v Blake Ellis | 7-6,6-7,2-5 |
| UTR Pro Tennis Series Brisbane | 2021/07/22 01:30 | Winter Meagher v Blake Ellis | 3-6,6-3,6-7 |
| UTR Pro Tennis Series Brisbane | 2021/07/20 00:00 | Timothy Gray v Blake Ellis | 1-6,5-7 |