Stadium: MTA 14 Round: 62 Ground: Clay
| ITF M25 Prague | 2021/10/05 08:00 | Filip Duda v Daniel Siniakov | 6-1,6-4 |
| ITF M25 Pardubice | 2021/09/23 12:30 | Daniel Siniakov v Eric Vanshelboim | 6-4,1-6,2-6 |
| ITF M25 Pardubice | 2021/09/22 11:05 | Daniel Siniakov v Stefanos Sakellaridis | 6-3,6-2 |
| ITF M25 Ricany | 2021/09/01 09:05 | Marek Gengel v Daniel Siniakov | 7-5,6-3 |
| 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 |