Stadium: Court 4 Round: 62 Ground: Hardcourt outdoor
| ITF M25 Jablonec Nad Nisou | 2023/05/28 11:30 | Tomas Zlatohlavek v Jakub Ostajewski | 6-3,6-1 |
| 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 Durguti, Besir | 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 Filip, Vladimir | 2-6,1-6 |
| UTR Pro Thessaloniki | 2023/04/24 05:00 | Mihai Razvan Marinescu v Jakub Ostajewski | 6-3,5-0 |
| ITF M15 Cancun | 2022/07/17 14:00 | Metz, David v Maxime St-Hilaire | 7-6,6-1 |