| UTR Pro Tennis Series Mulheim | 2021/10/13 10:20 | Ivan Marrero Curbelo v Balderas, Diego | 6-1,5-1 |
| UTR Pro Tennis Series Mulheim | 2021/10/12 07:00 | Ivan Marrero Curbelo v Willems, Johann | 2-6,3-5 |
| UTR Pro Tennis Series Mulheim | 2021/10/11 12:15 | Willems, Johann v Dhoe, Benjamin | 6-2,5-1 |
| UTR Pro Tennis Series Mulheim | 2021/09/23 09:30 | Willems, Johann v Alen Moritz Hodzic | 0-0 |
| UTR Pro Tennis Series Mulheim | 2021/09/20 08:00 | Willems, Johann v Broville, Maxence | 0-0 |
| German Premier League | 2020/07/27 17:05 | Paul Valsecchi v Willems, Johann | 1-6,7-5,6-2 |
| ITF - M15 Monastir | 2020/03/09 13:30 | Willems, Johann v Dahiya, Paras | 3-6,6-2,6-10 |
| ITF - M15 Monastir | 2020/03/09 08:00 | Willems, Johann v Lewie Lane | 6-4,6-4 |
| ITF - M15 Monastir | 2020/03/08 08:00 | Adil Kalyanpur v Willems, Johann | 2-6,2-6 |