Stadium: Court M Round: 26 Ground: Clay
| ITF Turkey F6 | 2017/02/18 08:00 | Christopher Heyman v Marc Sieber | 3-6,1-6 |
| ITF Turkey F17 | 2016/05/01 11:00 | Marc Sieber v Christopher Heyman | 6-3,6-0 |
| ITF Germany F8 | 2018/07/17 14:05 | Viktor Durasovic v Marc Sieber | 3-6,2-6 |
| Challenger Caltanissetta | 2018/06/12 08:00 | Marcelo Arevalo v Marc Sieber | 1-6,6-1,7-5 |
| Challenger Caltanissetta Qual | 2018/06/11 10:15 | Joao Souza v Marc Sieber | 6-2,3-6,4-6 |
| Challenger Caltanissetta Qual | 2018/06/10 11:30 | Marc Sieber v Pawel Juszczak | 6-0,6-1 |
| Challenger Caltanissetta Qual | 2018/06/09 13:25 | Mikhail Balmashev v Marc Sieber | 0-6,1-6 |
| Challenger Prostejov Qual | 2018/06/03 15:25 | Marc Sieber v Jan Satral | 6-4,3-6,4-6 |
| Challenger Prostejov Qual | 2018/06/03 09:45 | Pavel Nejedly v Marc Sieber | 1-6,5-7 |
| ITF Hungary F2 | 2018/05/18 08:00 | Mate Valkusz v Marc Sieber | 6-1,6-1 |
| ITF Germany F8 | 2018/07/18 15:10 | Pavle Daljev v Christopher Heyman | 3-6,4-6 |
| ITF Belgium F3 | 2018/07/06 15:00 | Christopher Heyman v Michael Geerts | 6-4,6-7,3-6 |
| ITF Belgium F3 | 2018/07/05 15:35 | Christopher Heyman v Nikita Mashtakov | 6-3,6-2 |
| ITF Belgium F3 | 2018/07/04 10:10 | Christopher Heyman v Felipe M Sarrasague | 6-2,6-4 |
| ITF Belgium F3 Qual | 2018/07/02 10:35 | Christopher Heyman v Robin Vanhauwe | 6-3,6-0 |
| ITF Belgium F3 Qual | 2018/07/01 12:00 | Christopher Heyman v Lautaro Agustin Falabella | 6-2,6-1 |
| ITF Belgium F3 Qual | 2018/06/30 07:30 | Christopher Heyman v Joaquin P M Bannen | 6-1,6-1 |
| ITF Germany F5 | 2018/06/28 13:30 | Christopher Heyman v Tim Ruehl | 6-3,6-7,1-6 |