Stadium: Court 2 Round: 26 Ground: Carpet indoor
| Challenger Iasi | 2021/07/13 12:15 | Zdenek Kolar v David Poljak | 6-2,7-5 |
| Challenger Iasi | 2021/07/12 08:00 | Vlad Andrei Dancu v David Poljak | 2-6,0-6 |
| Challenger Iasi | 2021/07/11 09:20 | Mircea-Alexandru Jecan v David Poljak | 4-6,0-6 |
| ITF M25 Wroclaw | 2021/06/29 13:25 | Uladzimir Ignatik v David Poljak | 6-0,6-2 |
| ITF M15 Bergamo | 2021/06/22 15:50 | David Poljak v Dali Blanch | 2-6,6-3,3-6 |
| Challenger Prostejov | 2021/06/15 09:35 | Alex Molcan v David Poljak | 6-3,6-3 |
| Challenger Prostejov | 2021/06/14 08:30 | Johannes Haerteis v David Poljak | 5-7,3-6 |
| Challenger Prostejov | 2021/06/13 09:00 | David Poljak v Sem Verbeek | 6-3,6-3 |
| ITF M25 Telfs | 2021/07/16 10:00 | Kirill Kivattsev v Ondrej Horak | 6-2,6-2 |
| ITF M25 Telfs | 2021/07/14 07:55 | George Botezan v Ondrej Horak | 6-4,2-6,5-7 |
| ITF M25 Telfs | 2021/07/13 07:30 | Neil Oberleitner v Ondrej Horak | 4-6,4-6 |
| ITF M25 Telfs | 2021/07/12 07:55 | Ondrej Horak v Samuel Puskar | 6-3,6-4 |
| ITF M25 Wroclaw | 2021/06/28 10:00 | Daniel Dutra Da Silva v Ondrej Horak | 3-6,0-6 |
| ITF M15 Skopje | 2021/06/07 08:30 | Leonid Sheyngezikht v Ondrej Horak | 6-0,7-5 |
| ITF M15 Skopje | 2021/06/06 09:00 | Ondrej Horak v Luigi Sorrentino | 6-0,1-6,11-9 |
| ITF M15 Skopje | 2021/05/30 09:30 | Ondrej Horak v Viktor Jovic | 4-6,3-6 |