Stadium: Court 2 Round: 25 Ground: Clay
| Challenger Szczecin | 2021/09/12 09:00 | Szymon Kielan v Alex Rybakov | 2-6,6-2,3-6 |
| Challenger Warsaw | 2021/08/26 13:00 | Lucas Miedler v Szymon Kielan | 7-5,6-4 |
| Challenger Warsaw | 2021/08/25 08:00 | Szymon Kielan v Goncalo Oliveira | 7-5,6-0 |
| ITF M15 Lodz | 2021/08/19 10:30 | Daniel Michalski v Szymon Kielan | 3-6,7-5,6-3 |
| ITF M15 Lodz | 2021/08/18 09:30 | Roman Andres Burruchaga v Szymon Kielan | 6-7,3-6 |
| ITF M15 Gdynia | 2021/08/12 10:25 | Szymon Kielan v Musialek, Alexis | 3-6,4-6 |
| ITF M15 Gdynia | 2021/08/11 14:25 | Johnson, Luke v Szymon Kielan | 1-6,6-7 |
| ITF M25 Grodzisk Mazowiecki | 2021/08/04 17:10 | David Poljak v Szymon Kielan | 7-5,6-3 |
| ITF M15 Chornomorsk | 2021/08/31 07:00 | Smirnov, Artem v Gabriele Maria Noce | 4-6,7-6,5-7 |
| ITF M15 Novomoskovsk | 2020/09/01 09:00 | Dzhavakian, Yurii v Smirnov, Artem | 6-3,6-4 |
| ITF - M15 Héraklion | 2019/12/13 09:55 | Smirnov, Artem v Vitaliy Sachko | 3-6,7-5,2-6 |
| ITF - M15 Héraklion | 2019/12/12 10:55 | Pervolarakis, Michail v Smirnov, Artem | 3-6,6-2,5-7 |
| ITF - M15 Héraklion | 2019/12/10 12:00 | Alexander Zgirovsky v Smirnov, Artem | 3-6,6-4,2-6 |
| ITF - M15 Héraklion | 2019/12/04 08:00 | Pervolarakis, Michail v Smirnov, Artem | 6-4,7-6 |
| ITF - M15 Héraklion | 2019/12/01 10:00 | Smirnov, Artem v Matija Pecotic | 3-6,5-7 |
| ITF - M15 Héraklion | 2019/11/30 10:25 | Smirnov, Artem v Bogdan Bobrov | 6-2,6-0 |