Stadium: Center Court Round: 45 Ground: Carpet indoor
| Challenger Eckental Qual | 2017/10/30 11:20 | Robin Kern v Marc Sieber | 6-4,6-2 |
| ITF Italy F25 | 2018/08/28 17:00 | Pasquale De Giorgio v Robin Kern | 4-6,3-6 |
| ITF Portugal F16 | 2018/08/22 09:00 | Nicolas Alvarez Varona v Robin Kern | 6-2,6-2 |
| ITF Germany F12 | 2018/08/16 13:10 | Aleksandre Metreveli v Robin Kern | 7-5,7-5 |
| ITF Germany F12 | 2018/08/14 15:00 | Moritz Hoffmann v Robin Kern | 2-6,3-6 |
| Challenger Blois Qual | 2018/06/16 12:15 | David Vega Hernandez v Robin Kern | 3-6,6-1,6-4 |
| Challenger Shymkent Qual | 2018/06/02 04:00 | Robin Kern v Shuichi Sekiguchi | 4-6,2-6 |
| Challenger Loughborough Qual | 2018/05/20 13:25 | Robin Kern v Andrea Vavassori | 1-6,2-6 |
| Challenger Loughborough Qual | 2018/05/19 15:50 | Robin Kern v Jack Draper | 6-4,6-4 |
| Challenger Mallorca | 2018/08/26 11:30 | Federico Zeballos v Marc Sieber | 3-6,6-1,6-3 |
| Challenger Meerbusch | 2018/08/14 12:30 | Marc Sieber v Johan Sebastien Tatlot | 6-7,6-4,4-6 |
| Challenger Meerbusch Qual | 2018/08/13 09:00 | Tristan Lamasine v Marc Sieber | 6-7,5-7 |
| Challenger Meerbusch Qual | 2018/08/12 09:40 | Marc Sieber v Adrian Oetzbach | 6-0,6-0 |
| Challenger Meerbusch Qual | 2018/08/11 11:45 | Mats Rosenkranz v Marc Sieber | 3-6,3-6 |
| Challenger Pullach Qual | 2018/08/04 09:00 | Marc Sieber v Julian Lenz | 4-6,6-4,4-6 |
| Challenger Liberec Qual | 2018/07/29 08:30 | Marc Sieber v Marvin Moeller | 2-6,5-7 |
| Challenger Liberec Qual | 2018/07/28 08:00 | Juan Pablo Ficovich v Marc Sieber | 3-6,6-3,3-6 |