Stadium: Court 2 Round: 25 Ground: Clay
| ITF M25 Heraklion | 2023/11/02 10:00 | Guy Den Ouden v Szymon Kielan | 7-5,6-0 |
| ITF M25 Heraklion | 2023/11/01 07:00 | Dali Blanch v Szymon Kielan | 6-7,6-2,3-6 |
| ITF M15 Heraklion | 2023/10/26 09:20 | Valentin Royer v Szymon Kielan | 6-3,6-2 |
| ITF M15 Heraklion | 2023/10/24 09:00 | Szymon Kielan v Kevin Edengren | 6-3,6-2 |
| ITF M15 Heraklion | 2023/10/19 06:30 | Oliver Ojakaar v Szymon Kielan | 7-6,7-6 |
| ITF M15 Heraklion | 2023/10/18 06:30 | Andreas Loizas v Szymon Kielan | 1-6,2-6 |
| ITF M15 Danderyd | 2023/09/19 12:25 | Sebastian Eriksson v Szymon Kielan | 6-2,6-3 |
| Challenger Szczecin | 2023/09/10 09:45 | Steven Diez v Szymon Kielan | 6-1,7-5 |
| ITF M15 Boca Raton | 2023/11/16 13:00 | John H Lithen v Arvid Nordquist | 2-6,5-7 |
| ITF M15 Fayetteville | 2023/11/01 20:50 | Joshua Sheehy v John H Lithen | 6-2,3-6,7-6 |
| ITF M15 Fayetteville | 2023/10/31 15:00 | Keshav Chopra v John H Lithen | 5-7,3-6 |
| ITF M15 Fayetteville | 2023/10/30 15:00 | Franco Ribero v John H Lithen | 3-6,1-6 |
| ITF M25 Ystad | 2023/08/17 08:45 | Eero Vasa v John H Lithen | 7-5,6-2 |
| ITF M25 Ystad | 2023/08/16 10:55 | John H Lithen v Sebastian Gima | 7-6,7-5 |
| ITF M15 Frankfurt Am Main | 2023/08/09 15:20 | Philip Florig v John H Lithen | 6-3,6-1 |
| ITF M15 Frankfurt Am Main | 2023/08/07 13:00 | John H Lithen v Sven Corbinais | 6-3,6-1 |