| UTR Pro Dubaï | 2023/02/01 05:00 | David Pichler v Willems, Johann | 6-3,7-5 |
| UTR Pro Dubaï | 2023/01/31 09:15 | Sylvester Emmanuel v Willems, Johann | 3-6,1-6 |
| UTR Pro Tennis Series Mulheim | 2022/10/03 11:00 | Pierre, Hugo v Willems, Johann | 7-6,1-0 |
| UTR Pro Tennis Series Mulheim | 2022/07/03 07:30 | Willems, Johann v Francisco Rocha | 3-6,1-3 |
| UTR Pro Tennis Series Mulheim | 2022/07/02 07:30 | Willems, Johann v Tom Gentzsch | 6-1,6-6 |
| UTR Pro Tennis Series Mulheim | 2022/07/01 06:00 | Willems, Johann v Calvo Barcelo, Fermin | 5-7,6-4,6-6 |
| UTR Pro Tennis Series Mulheim | 2022/06/30 07:30 | Willems, Johann v Leopold Zima | 6-3,5-3 |
| UTR Pro Tennis Series Mulheim | 2022/06/29 09:00 | Rodeia, Andre v Willems, Johann | 3-6,6-7 |
| UTR Pro Dubaï | 2023/01/31 07:45 | David Pichler v Kai Lemstra | 6-1,6-4 |
| UTR Pro Dubaï | 2023/01/30 08:00 | Kai Lemstra v Lohithaksha Bathrinath | 6-1,6-2 |
| ITF M25 Veigy-Foncenex | 2023/01/11 15:50 | Mikalai Haliak v Kai Lemstra | 6-2,7-6 |
| ITF M25 Veigy-Foncenex | 2023/01/09 11:10 | Kai Lemstra v Evan Jarzaguet | 6-2,6-2 |
| ITF M25 Veigy-Foncenex | 2023/01/08 09:00 | Kai Lemstra v Max Cunat | 6-4,6-2 |
| Trnava, Singles Main, M-ITF-SVK-03A | 2022/12/07 09:00 | Daniel Siniakov v Kai Lemstra | 6-1,6-1 |
| ITF - M25 Trnava | 2022/12/06 09:00 | Kai Lemstra v Alfred Almasi | 7-5,6-0 |
| ITF - M25 Trnava | 2022/12/05 09:00 | Kai Lemstra v Razvan Baiant | 6-2,7-6 |