Stadium: Court 5 Round: 25 Ground: Hardcourt outdoor
| ITF M15 - Oberhaching | 2020/02/16 15:00 | Christoph Negritu v Kai Lemstra | 7-6,6-1 |
| ITF Germany F9 | 2018/07/24 14:45 | Kai Lemstra v Christoph Negritu | 2-6,4-6 |
| ITF - M15 - Monastir | 2021/03/08 18:00 | Anis Ghorbel v Kai Lemstra | 6-3,6-4 |
| ITF - M15 - Monastir | 2021/03/08 13:30 | Sabit Suntic v Kai Lemstra | 3-6,6-4,8-10 |
| ITF - M15 - Monastir | 2021/03/07 10:30 | Facundo Yunis v Kai Lemstra | 6-7,3-6 |
| ITF - M15 - Monastir | 2021/03/01 08:00 | Noah Lopez v Kai Lemstra | 3-6,7-5,10-7 |
| ITF - M15 - Monastir | 2021/02/28 08:00 | Goran Duquesne v Kai Lemstra | 0-6,2-6 |
| ITF M15 - Bratislava | 2020/11/24 09:00 | Kai Lemstra v Kristof Minarik | 2-6,4-6 |
| ITF M15 - Bratislava | 2020/11/23 14:00 | Kai Lemstra v Patrik Jancovic | 6-2,6-2 |
| ITF M15 - Sarreguemines | 2020/10/26 15:35 | Kai Lemstra v Karlo Cubelic | 4-6,7-5,8-10 |
| ITF - M15 - Monastir | 2021/03/02 08:30 | Constantin Schmitz v Christoph Negritu | 6-4,7-6 |
| ITF - M15 - Monastir | 2021/02/24 08:00 | Colin Sinclair v Christoph Negritu | 6-1,7-5 |
| Tyskland - Mästerskap | 2020/12/10 10:30 | Jakob Schnaitter v Christoph Negritu | 7-6,7-5 |
| Tyskland - Mästerskap | 2020/12/08 15:00 | Marvin Moeller v Christoph Negritu | 6-7,6-3,3-6 |
| ITF M15 - Alkmaar | 2020/08/27 09:00 | Shintaro Mochizuki v Christoph Negritu | 6-4,7-5 |
| ITF M15 - Alkmaar | 2020/08/25 14:40 | Christoph Negritu v Carlos Boluda-Purkiss | 6-3,4-6,6-4 |
| DTB German Pro Series | 2020/06/27 12:00 | Daniel Altmaier v Christoph Negritu | 6-4,7-5 |
| DTB German Pro Series | 2020/06/26 14:40 | Daniel Altmaier v Christoph Negritu | 7-6,6-1 |