Stadium: Court 11 Round: 166 Ground: Clay
| Challenger Campinas | 2018/09/29 13:55 | Duran, Guillermo v Pedro Sakamoto | 1-6,2-6 |
| Challenger Szczecin | 2018/09/10 09:00 | Tomas Barrios Vera v Duran, Guillermo | 6-7,6-1,6-3 |
| Challenger Szczecin | 2018/09/09 10:35 | Duran, Guillermo v Vanneste, Jeroen | 6-1,6-2 |
| Challenger Szczecin | 2018/09/08 12:15 | Duran, Guillermo v Nikita Mashtakov | 7-5,5-7,7-6 |
| Challenger Bordeaux Qual | 2018/05/12 11:45 | Duran, Guillermo v Riffice, Sam | 2-6,6-7 |
| Challenger Aix en Provence Qual | 2018/05/06 09:00 | Duran, Guillermo v Antoine Escoffier | 3-6,2-6 |
| Challenger Aix en Provence Qual | 2018/05/05 08:30 | Geens, Clement v Duran, Guillermo | 3-6,2-6 |
| Challenger Francavilla Qual | 2018/04/21 14:15 | Antoine Hoang v Duran, Guillermo | 6-2,6-3 |
| Saarlouis, Singles Qualifying M-ITF-GER-07A | 2019/07/04 11:45 | Guttau, Niklas v Boehler, Dominik | 4-6,5-7 |
| Saarlouis, Singles Qualifying M-ITF-GER-07A | 2019/07/02 10:00 | Erler, Alexander v Guttau, Niklas | 4-6,6-4,5-7 |
| Kaltenkirchen, Singles Qualifying M-ITF-GER-05A | 2019/06/12 10:30 | Eriksson, Markus v Guttau, Niklas | 6-3,6-1 |
| Kaltenkirchen, Singles Qualifying M-ITF-GER-05A | 2019/06/11 18:25 | Guttau, Niklas v Rinky Hijikata | 6-3,6-1 |
| ITF - M15 Antalya | 2019/05/25 07:45 | Guttau, Niklas v Heyman, Christopher | 5-7,2-6 |
| ITF - M15 Antalya | 2019/05/23 09:05 | Guttau, Niklas v Obert, Adrian | 4-6,6-4,7-6 |
| ITF - M15 Antalya | 2019/05/22 11:30 | Paul Woerner v Guttau, Niklas | 1-6,2-6 |
| ITF - M15 Antalya | 2019/04/25 10:40 | Heyman, Christopher v Guttau, Niklas | 7-6,7-5 |