Stadium: Court M Round: 62 Ground: Clay
| ITF Germany F8 Qual | 2018/07/15 12:30 | Drzewiecki, Karol v Seibert, Tim | 5-7,2-6 |
| ITF Germany F5 | 2018/06/26 13:40 | Seibert, Tim v Hirschmueller, Christian | 2-6,6-3,3-6 |
| ITF Germany F16 | 2017/10/22 08:00 | Kai Lemstra v Seibert, Tim | 3-6,1-6 |
| ITF Germany F16 | 2017/10/22 08:00 | Seibert, Tim v Guenther, Valentin | 6-4,3-6,4-6 |
| ITF Germany F15 | 2017/10/16 08:00 | Ryan Peniston v Seibert, Tim | 6-1,6-4 |
| ITF Germany F11 | 2017/08/13 13:00 | Aichhorn, Jakob v Seibert, Tim | 6-4,6-7,6-1 |
| ITF Germany F11 | 2017/08/13 08:00 | Seibert, Tim v Flinner, Marek | 7-6,6-2 |
| ITF Germany F10 | 2017/08/06 11:00 | Dischinger, Eduardo v Seibert, Tim | 6-0,7-5 |
| ITF Germany F8 Qual | 2018/07/15 12:30 | Sudzum, Marcel Marlon v Guttau, Niklas | 4-6,0-6 |
| ITF Germany F8 Qual | 2018/07/15 08:30 | Marlon Vankan v Guttau, Niklas | 1-6,2-6 |
| Challenger Braunschweig Qual | 2018/07/07 09:30 | Kimmer Coppejans v Guttau, Niklas | 6-3,6-1 |
| ITF Germany F4 | 2018/06/19 10:45 | Gonzalez, Wilfredo v Guttau, Niklas | 6-3,7-6 |
| Turkey F15, Singles Qualifying | 2018/04/14 07:30 | Guttau, Niklas v Louroi Martinez | 1-6,6-2,0-6 |
| Turkey F14, Singles Qualifying | 2018/04/07 11:00 | Guttau, Niklas v Hellfritsch, Lucas | 4-6,3-6 |
| ITF Turkey F13 | 2018/03/31 11:00 | Felipe Meligeni Rodrigues Alves v Guttau, Niklas | 6-3,6-1 |
| ITF Tunisia F32 | 2017/10/23 08:30 | Vibert, Francois Arthur v Guttau, Niklas | 6-1,6-2 |