Stadium: Court 2 Round: 62 Ground: Hardcourt outdoor
| ITF - M15 Sharm El Sheikh | 2021/03/07 16:00 | Guttau, Niklas v Makzoume, Yacoub | 6-3,6-2 |
| ITF - M15 Monastir | 2021/02/28 10:30 | Guttau, Niklas v Stefano Reitano | 3-6,6-3,7-10 |
| ITF - M15 Monastir | 2021/02/22 08:00 | Samir Hamza Reguig v Guttau, Niklas | 6-7,6-1,11-9 |
| ITF - M15 Monastir | 2021/02/21 12:00 | Milan Drinic v Guttau, Niklas | 4-6,4-6 |
| German Championship | 2020/12/10 14:00 | Tim Handel v Guttau, Niklas | 7-6,7-6 |
| DTB German Pro Series | 2020/06/26 08:00 | Guttau, Niklas v Florig, Philip | 6-2,7-6 |
| DTB German Pro Series | 2020/06/25 09:20 | Peter Heller v Guttau, Niklas | 6-1,6-2 |
| DTB German Pro Series | 2020/06/24 10:00 | Guttau, Niklas v Florig, Philip | 6-7,6-2,6-1 |
| ITF - M15 Sharm El Sheikh | 2021/03/07 16:00 | Mirko Lagasio v Sada, Iacopo | 6-3,4-6,10-5 |