Stadium: Center Court Round: 25 Ground: Clay
| Challenger Warsaw | 2021/08/23 09:00 | Zielinski, Jan v Aldin Setkic | 1-6,6-2,7-5 |
| Challenger Warsaw | 2021/08/22 11:15 | Skander Mansouri v Zielinski, Jan | 7-5,3-6,3-6 |
| Polish National Tour | 2021/07/11 13:00 | Zielinski, Jan v Filip Peliwo | 5-7,2-6 |
| ITF M25 Poznan | 2020/08/26 07:55 | Zielinski, Jan v Vit Kopriva | 4-6,2-6 |
| Polish National Tour | 2020/08/18 07:30 | Pawel Juszczak v Zielinski, Jan | 6-2,6-0 |
| Polish National Tour | 2020/08/16 14:00 | Galus, Piotr v Zielinski, Jan | 3-6,3-6 |
| Polish National Tour | 2020/08/01 09:00 | Pawel Juszczak v Zielinski, Jan | 3-6,6-3,7-5 |
| Polish National Tour | 2020/07/30 09:45 | Piotr Grynkowski v Zielinski, Jan | 2-6,6-4,2-6 |
| Luedenscheid, Germany | 2021/08/18 10:45 | Mirza Basic v Tristan Lamasine | 7-6,6-2 |
| Luedenscheid, Germany | 2021/08/17 08:00 | Tristan Lamasine v Evgeny Karlovskiy | 6-3,6-3 |
| Poznan, Poland | 2021/07/27 11:45 | Jiri Lehecka v Tristan Lamasine | 6-3,7-5 |
| Challenger Todi | 2021/07/13 15:00 | Tristan Lamasine v Vilella Martinez, Mario | 2-6,6-7 |
| Milan, Italy | 2021/06/23 09:00 | Tristan Lamasine v Pedro Cachin | 1-6,4-6 |
| Milan, Italy | 2021/06/22 08:30 | Tristan Lamasine v Arnaboldi, Andrea | 3-6,6-1,7-5 |
| Challenger - Aix en Provence | 2021/06/18 09:00 | Manuel Guinard v Tristan Lamasine | 6-7,6-3,6-3 |
| Challenger - Aix en Provence | 2021/06/16 08:30 | Fratangelo, Bjorn v Tristan Lamasine | 5-7,3-6 |