Stadium: Court 1 Round: 26 Ground: Clay
| ITF Czech Republic F6 | 2018/07/09 09:05 | Guido Ivan Justo v Semjan, Marek | 5-7,6-2,4-6 |
| Czech Republic F6, Singles Qualifying | 2018/07/08 08:00 | Semjan, Marek v Remy Bertola | 7-5,6-4 |
| Czech Republic F6, Singles Qualifying | 2018/07/07 07:30 | Semjan, Marek v Holis, Stepan | 6-1,6-0 |
| ITF Bosnia and Herzegovina F3 | 2018/05/31 15:00 | Semjan, Marek v Hansson, Gustav | 4-6,1-6 |
| ITF Bosnia and Herzegovina F3 | 2018/05/30 09:00 | Semjan, Marek v Nikolic, Milos | 6-3,6-1 |
| ITF Poland F4 | 2018/05/24 08:00 | Pawel Juszczak v Semjan, Marek | 3-6,6-3,6-1 |
| ITF Poland F4 | 2018/05/21 09:00 | Semjan, Marek v Mikula, Michal | 7-5,6-3 |
| ITF Czech Republic F1 | 2018/05/15 10:30 | Semjan, Marek v Laurent Lokoli | 5-7,0-6 |
| ITF Czech Republic F6 | 2018/07/09 10:30 | Alex Molcan v Mertl, Jan | 2-6,4-6 |
| ITF Czech Republic F5 | 2018/07/05 08:30 | Patrik Rikl v Mertl, Jan | 7-6,6-4 |
| ITF Czech Republic F5 | 2018/07/04 09:35 | Mertl, Jan v Pavel Kotov | 7-6,6-3 |
| ITF Czech Republic F5 | 2018/07/03 09:30 | Stepanek, Antonin v Mertl, Jan | 6-3,1-6,2-6 |
| ITF Czech Republic F4 | 2018/06/28 13:00 | Torebko, Peter v Mertl, Jan | 7-6,6-4 |
| ITF Czech Republic F4 | 2018/06/27 09:10 | Konecny, Michal v Mertl, Jan | 4-6,7-5,2-6 |
| ITF Czech Republic F4 | 2018/06/26 08:00 | Mertl, Jan v Oscar Jose Gutierrez | 7-6,6-3 |
| Challenger Prostejov Qual | 2018/06/04 10:00 | Cuevas, Martin v Mertl, Jan | 6-4,7-6 |