Stadium: Court 3 Round: 25 Ground: Clay
| Challenger Prague | 2021/08/22 08:00 | Marek Gengel v Alex Rybakov | 5-7,1-6 |
| ITF M25 Prostejov | 2021/08/18 07:55 | Alex Rybakov v Marek Gengel | 6-3,6-3 |
| ITF M25 Prostejov | 2021/08/17 07:55 | Marek Gengel v Christopher Patzanovsky | 6-2,6-0 |
| Challenger Prague | 2021/08/08 11:20 | Marek Gengel v Emilio Nava | 4-6,3-6 |
| ITF M25 Grodzisk Mazowiecki | 2021/08/04 15:00 | Philip Bachmaier v Marek Gengel | 6-3,6-4 |
| ITF M15 Castelo Branco | 2021/07/29 13:15 | Marek Gengel v Daniel Batista | 4-6,6-3,3-6 |
| ITF M15 Castelo Branco | 2021/07/28 08:30 | Marek Gengel v Ray Ho | 6-2,2-6,6-3 |
| ITF M25 Idanha-A-Nova | 2021/07/22 11:45 | Clement Chidekh v Marek Gengel | 6-4,7-6 |
| Challenger Prague | 2021/08/24 13:45 | Daniel Siniakov v Igor Sijsling | 4-6,3-6 |
| ITF M25 Prostejov | 2021/08/17 09:15 | Martin Krumich v Daniel Siniakov | 3-6,6-4,7-5 |
| Challenger Liberec | 2021/08/03 15:10 | Nikola Milojevic v Daniel Siniakov | 7-5,6-0 |
| Challenger Liberec | 2021/08/02 10:35 | Daniel Siniakov v David Vega Hernandez | 6-3,7-5 |
| Challenger Liberec | 2021/08/01 16:30 | Geoffrey Blancaneaux v Daniel Siniakov | 2-6,3-6 |
| ITF M15 Poprad | 2021/07/06 07:55 | Illya Beloborodko v Daniel Siniakov | 3-6,7-6,7-5 |
| ITF M15 Poprad | 2021/07/05 08:00 | Calin Manda v Daniel Siniakov | 3-6,0-6 |
| ITF M15 Poprad | 2021/07/04 11:00 | Lukas Pokorny v Daniel Siniakov | 6-2,4-6,5-10 |