Stadium: Grandstand 4 Round: 54 Ground: Hardcourt outdoor
| ITF M25 Budapest | 2021/09/26 11:00 | Mark Havlicek v Jakub Katuch | 6-2,6-4 |
| ITF M25 Pardubice | 2021/09/23 07:30 | Mark Havlicek v Pavel Nejedly | 6-7,6-7 |
| ITF M25 Pardubice | 2021/09/21 09:30 | Tim Handel v Mark Havlicek | 7-5,6-1 |
| ITF M25 Pardubice | 2021/09/20 10:00 | Vitek Horak v Mark Havlicek | 6-7,3-6 |
| ITF M25 Ricany | 2021/08/31 08:00 | Jonas Forejtek v Mark Havlicek | 6-2,6-1 |
| ITF M25 Ricany | 2021/08/30 10:00 | Mark Havlicek v Caspar Schuetze | 6-1,6-2 |
| ITF M25 Prostejov | 2021/08/18 09:15 | Zsombor Piros v Mark Havlicek | 6-3,6-2 |
| ITF M25 Prostejov | 2021/08/17 12:15 | Mark Havlicek v Simon Malis | 6-1,6-2 |
| ITF M15 Vyshkovo | 2021/09/20 07:00 | Horst Rieder v Danylo Veremeychuk | 6-2,1-6,5-10 |
| ITF M15 Vyshkovo | 2021/09/20 06:00 | Horst Rieder v Oleksiy Kalynyuk | 6-3,6-0 |
| ITF M15 Ulcinj | 2021/09/06 07:30 | Gabriele Piraino v Horst Rieder | 7-6,6-1 |
| ITF M15 Ulcinj | 2021/08/29 12:30 | Lautaro Agustin Falabella v Horst Rieder | 6-3,2-6,10-7 |
| ITF M25 Bolzano | 2021/08/02 14:25 | Horst Rieder v Dominique Graf | 6-7,3-6 |
| ITF M25 Bolzano | 2021/08/01 07:30 | Horst Rieder v Gabriele Camilli | 6-1,7-6 |
| ITF M25 Ricany | 2019/09/22 09:00 | Michael Paty v Horst Rieder | 2-6,4-6 |
| ITF M25 Santa Margherita | 2019/09/18 15:40 | Horst Rieder v Riccardo Di Nocera | 3-6,7-5,4-6 |