Round: 62 Ground: Hardcourt outdoor
| ITF Germany F2 Qual | 2018/01/21 08:30 | Lang, Robin v Nikolas, Klemen | 6-2,6-4 |
| ITF Egypt F20 | 2017/11/18 08:00 | Nikolas, Klemen v Ren Nakamura | 4-6,2-6 |
| ITF Egypt F34 | 2017/11/12 08:00 | Nikolas, Klemen v Daisuke Sumizawa | 0-6,5-7 |
| ITF Egypt F34 | 2017/11/11 08:00 | Nikolas, Klemen v Simpson, Valewis | 6-3,7-6 |
| ITF Croatia F4 Qual | 2017/03/25 10:00 | Nikolas, Klemen v Dabryian, Artsiom | 2-6,6-0,3-6 |
| ITF Croatia F3 | 2017/03/19 08:30 | Nikolas, Klemen v Kralj, Kevin | 3-6,3-6 |
| ITF Croatia F2 | 2017/03/12 08:30 | Pompei, Edoardo v Nikolas, Klemen | 7-5,6-2 |
| ITF Croatia F2 | 2017/03/11 10:00 | Krneta, Nino v Nikolas, Klemen | 5-7,4-6 |
| ITF Turkey F32 | 2018/10/13 07:00 | Guttau, Niklas v Leuch, Vital Flurin | 6-2,6-4 |
| ITF Turkey F31 | 2018/10/11 07:00 | Guttau, Niklas v Stevens, Bart | 4-6,2-6 |
| ITF Turkey F31 | 2018/10/09 09:10 | Guttau, Niklas v Iordache, Sorin Andrei | 6-3,5-7,6-3 |
| ITF Turkey F31 | 2018/10/08 07:00 | Liska, Tomas v Guttau, Niklas | 4-6,6-2,2-6 |
| ITF Turkey F31 | 2018/10/07 07:00 | Wakita, Shunsuke v Guttau, Niklas | 4-6,3-6 |
| ITF Turkey F31 | 2018/10/06 07:00 | Guttau, Niklas v Myagkov, Dmitry | 6-2,6-3 |
| ITF Turkey F30 | 2018/10/02 07:00 | Vanneste, Jeroen v Guttau, Niklas | 6-2,6-3 |
| ITF Turkey F30 | 2018/10/01 07:30 | Guttau, Niklas v Vicentiu Andrei Niculescu | 6-3,6-0 |