| Giraldilla Int. - Mixed dubbel | 2018/10/30 18:45 | David Kramer v Kai Schaefer | W | 0-2 |
| Giraldilla Int. - Mixed dubbel | 2018/09/28 08:30 | Kai Schaefer v Subhankar Dey | L | 1-2 |
| Giraldilla Int. - Mixed dubbel | 2018/09/23 14:00 | Harsheel Dani v Kai Schaefer | W | 1-2 |
| Giraldilla Int. - Mixed dubbel | 2018/09/23 09:20 | Iikka Heino v Kai Schaefer | W | 0-2 |
| Giraldilla Int. - Mixed dubbel | 2018/09/22 12:00 | Rasmus Messerschmidt v Kai Schaefer | W | 0-2 |
| Giraldilla Int. - Mixed dubbel | 2018/08/29 12:50 | Yu Igarashi v Kai Schaefer | L | 2-0 |
| All England Open | 2018/07/31 09:40 | Kai Schaefer v Hans-Kristian Vittinghus | L | 1-2 |
| Swiss Open - Damdubbel - Kval | 2018/07/17 00:55 | Kai Schaefer v Firman Abdul Kholik | L | 1-2 |
| French Open | 2018/10/23 10:40 | Mark Caljouw v Hans-Kristian Vittinghus | L | 1-2 |
| All England Open | 2018/10/17 16:00 | Anders Antonsen v Mark Caljouw | L | 2-0 |
| Dutch Open | 2018/10/13 15:30 | Mark Caljouw v Sourabh Verma | L | 0-2 |
| Dutch Open | 2018/10/12 16:30 | Mark Caljouw v Joo Ven Soong | W | 2-0 |
| Dutch Open | 2018/10/11 16:25 | Mark Caljouw v B.R. Sankeerth | W | 2-0 |
| Dutch Open | 2018/10/10 13:55 | Mark Caljouw v Jacob Nilsson | W | 2-0 |
| All England Open | 2018/09/19 04:00 | Mark Caljouw v Suppanyu Avihingsanon | L | 0-2 |
| All England Open | 2018/09/13 05:30 | Mark Caljouw v Khosit Phetpradab | L | 0-2 |