Stadium: Court 1 Round: 54 Ground: Carpet indoor
| ITF Czech Republic F7 | 2018/10/22 14:00 | Kai Lemstra v Vitek Horak | 6-3,6-2 |
| Challenger Ismaning | 2018/10/16 15:25 | Gregoire Barrere v Kai Lemstra | 7-6,6-3 |
| ITF Germany F15 | 2018/10/09 12:00 | Kai Lemstra v Sandro Ehrat | 1-6,4-6 |
| ITF Germany F14 | 2018/10/04 12:35 | Kai Lemstra v Paul Cayre | 6-4,3-6,4-6 |
| ITF Germany F14 | 2018/10/03 15:50 | Louis Wessels v Kai Lemstra | 6-7,6-1,4-6 |
| ITF Germany F13 | 2018/08/20 09:00 | Kai Lemstra v Jordi Walder | 3-6,6-1,3-6 |
| ITF Germany F12 | 2018/08/15 15:00 | Dan Added v Kai Lemstra | 7-5,6-2 |
| ITF Slovakia F2 | 2018/07/31 07:00 | Kai Lemstra v Samuel Hodor | 4-6,2-6 |
| ITF Czech Republic F7 | 2018/10/22 13:00 | Daniel Vrba v Piotr Grynkowski | 6-4,4-6,3-6 |
| ITF Germany F15 | 2018/10/11 13:50 | Denis Matsukevich v Piotr Grynkowski | 6-4,6-2 |
| ITF Germany F15 | 2018/10/10 12:10 | Leonard Von Hindte v Piotr Grynkowski | 6-7,6-1,3-6 |
| ITF Germany F15 | 2018/10/08 08:00 | Piotr Grynkowski v Thorsten Sollie | 7-5,7-5 |
| ITF Poland F8 | 2018/08/21 13:00 | Piotr Grynkowski v Jelle Sels | 3-6,2-6 |
| ITF Poland F8 | 2018/08/20 09:30 | Robert Strombachs v Piotr Grynkowski | 1-6,1-6 |
| ITF Poland F7 | 2018/08/14 14:50 | Piotr Grynkowski v Vladyslav Orlov | 5-7,0-6 |
| ITF Poland F7 | 2018/08/13 10:20 | Piotr Grynkowski v Mikolaj Borkowski | 6-3,6-3 |