Stadium: Court 6 Round: 54 Ground: Hardcourt indoor
| ITF - M15 Antalya | 2019/09/19 07:00 | Zielinski, Jan v Marsel Ilhan | 5-7,4-6 |
| ITF - M15 Antalya | 2019/09/18 07:40 | Zielinski, Jan v Alejandro H Franco | 6-3,7-6 |
| Challenger Szczecin | 2019/09/09 12:15 | Kacper Zuk v Zielinski, Jan | 6-7,7-6,6-2 |
| ITF M25 Poznan | 2019/08/20 12:00 | Denis Yevseyev v Zielinski, Jan | 7-6,6-0 |
| Bydgoszcz, Singles Qualifying M-ITF-POL-04A | 2019/08/17 13:20 | Daniel Michalski v Zielinski, Jan | 6-3,6-4 |
| Bydgoszcz, Singles Qualifying M-ITF-POL-04A | 2019/08/16 13:30 | Dougaz, Aziz v Zielinski, Jan | 3-6,3-6 |
| Bydgoszcz, Singles Qualifying M-ITF-POL-04A | 2019/08/15 08:00 | Zielinski, Jan v Wojcik, Yann | 6-3,6-4 |
| Bydgoszcz, Singles Qualifying M-ITF-POL-04A | 2019/08/13 12:00 | Smola, Maciej v Zielinski, Jan | 3-6,4-6 |
| Kalmar, Singles M-ITF-SWE-02A | 2019/05/14 09:40 | Ruzgas, Marius v Johansson, Oliver | 7-6,6-3 |
| Kalmar, Singles M-ITF-SWE-02A | 2019/05/13 13:15 | Johansson, Oliver v Arvid Nordquist | 7-6,6-2 |