Stadium: Campo 2 Round: 45 Ground: Clay
| Challenger Heilbronn Qual | 2018/05/12 11:30 | Mikhail Balmashev v Marc Giner | 6-4,4-6,3-6 |
| ITF Turkey F44 | 2017/11/22 07:10 | Mikhail Balmashev v Khumoyun Sultanov | 1-6,0-6 |
| 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 Hungary F2 | 2018/05/17 14:55 | Emil Ruusuvuori v Marc Sieber | 2-6,3-6 |
| ITF Hungary F2 | 2018/05/16 10:10 | Gabor Borsos v Marc Sieber | 1-6,7-6,1-6 |
| ITF Hungary F2 | 2018/05/15 12:30 | David Szintai v Marc Sieber | 4-6,3-6 |
| ITF Hungary F1 | 2018/05/11 10:45 | Mate Valkusz v Marc Sieber | 6-2,6-2 |
| ITF Hungary F1 | 2018/05/10 11:05 | Kenneth Raisma v Marc Sieber | 4-6,6-0,5-7 |