Stadium: Court 4 Round: 62 Ground: Clay
| ITF M15 Warmbad-Villach | 2023/05/21 10:00 | Jakub Ostajewski v Jimmy Yang | 4-6,5-7 |
| ITF M15 Warmbad-Villach | 2023/05/21 07:00 | Jakub Ostajewski v Zan M Mihovec | 6-0,6-0 |
| UTR Pro Thessaloniki | 2023/04/29 05:00 | Jakub Ostajewski v Besir Durguti | 1-6,4-6 |
| UTR Pro Thessaloniki | 2023/04/28 08:00 | Jakub Ostajewski v Enrique Bogo | 6-2,1-6,3-6 |
| UTR Pro Thessaloniki | 2023/04/26 05:00 | Jakub Ostajewski v Christos Antonopoulos | 2-6,0-6 |
| UTR Pro Thessaloniki | 2023/04/25 09:08 | Jakub Ostajewski v Vladimir Filip | 2-6,1-6 |
| UTR Pro Thessaloniki | 2023/04/24 05:00 | Mihai Razvan Marinescu v Jakub Ostajewski | 6-3,5-0 |
| UTR Pro Florida | 2023/04/02 13:00 | Azariah Rusher v Jakub Ostajewski | 3-6,6-7 |