Stadium: Center Court Round: 46 Ground: Carpet indoor
| Challenger Eckental | 2018/10/27 07:30 | Igor Sijsling v Lukas Klein | 7-6,6-3 |
| Challenger Como | 2018/08/25 12:10 | Igor Sijsling v Facundo Arguello | 5-7,1-6 |
| Challenger Lexington | 2018/07/31 17:55 | Ronnie Schneider v Igor Sijsling | 6-2,6-4 |
| ITF Germany F5 | 2018/06/27 15:25 | Filip Bergevi v Igor Sijsling | 6-1,6-2 |
| ITF Germany F5 | 2018/06/25 09:00 | Igor Sijsling v Jannik Rother | 6-1,6-3 |
| ITF Germany F5 | 2018/06/25 08:00 | Igor Sijsling v Quentin Folliot | 6-2,6-4 |
| Challenger Loughborough Qual | 2018/05/21 12:20 | Igor Sijsling v Jurij Rodionov | 6-7,3-6 |
| Challenger Loughborough Qual | 2018/05/20 14:30 | Igor Sijsling v Peter Bothwell | 6-4,6-2 |
| Challenger Eckental | 2018/10/27 08:45 | Tobias Simon v Aldin Setkic | 3-6,7-6,7-5 |
| Challenger Brest | 2018/10/21 13:45 | Tomislav Brkic v Tobias Simon | 6-2,6-0 |
| Challenger Brest | 2018/10/20 13:05 | Arthur Rinderknech v Tobias Simon | 6-7,7-6,3-6 |
| Challenger Ismaning | 2018/10/14 12:40 | Tobias Simon v Alexander Erler | 6-7,6-4,6-7 |
| Challenger Ismaning | 2018/10/13 17:10 | Evan Furness v Tobias Simon | 2-6,6-7 |
| Challenger Ortisei | 2018/10/09 08:30 | Tobias Simon v Ricardas Berankis | 6-7,4-6 |
| Challenger Ortisei | 2018/10/08 08:00 | Tobias Simon v Aldin Setkic | 7-6,6-7,7-6 |
| Challenger Ortisei | 2018/10/07 08:00 | Christopher Heyman v Tobias Simon | 3-6,6-7 |