Stadium: Court 7 Round: 62 Ground: Clay
| ITF M25 Most | 2021/05/23 14:00 | Martin Damm v Ondrej Horak | 7-5,6-4 |
| ITF M25 Jablonec Nad Nisou | 2021/05/17 07:30 | Ondrej Horak v Tomas Papik | 1-6,4-6 |
| ITF M25 Jablonec Nad Nisou | 2021/05/16 08:30 | George Loffhagen v Ondrej Horak | 5-7,1-6 |
| ITF M25 Praha | 2021/05/10 08:00 | Jan Satral v Ondrej Horak | 6-1,6-2 |
| ITF M25 Praha | 2021/05/09 10:00 | Ondrej Horak v Jan Jermar | 7-6,6-3 |
| ITF M15 Sibenik | 2021/04/20 08:00 | Alen Rogic-Hadzalic v Ondrej Horak | 6-1,6-4 |
| ITF M15 Sibenik | 2021/04/19 12:15 | Ondrej Horak v Boris Butulija | 6-2,7-6 |
| ITF M15 Sharm El Sheikh | 2021/03/24 11:20 | Ondrej Horak v Paul Jubb | 2-6,0-6 |
| ITF M25 Kiseljak | 2021/05/24 12:15 | Viktor Jovic v Nicolas Zanellato | 6-2,3-6,8-10 |
| ITF M25 Kiseljak | 2021/05/23 12:00 | Viktor Jovic v Michel Hopp | 7-5,4-6,10-6 |
| ITF M15 Brčko | 2021/05/22 07:30 | Matheus P De Almeida v Viktor Jovic | 6-1,6-0 |
| ITF M15 Brčko | 2021/05/21 13:25 | Aleksandar Tomas v Viktor Jovic | 0-6,1-6 |
| ITF M15 Brčko | 2021/05/21 10:10 | Dusan Obradovic v Viktor Jovic | 2-6,1-6 |
| ITF M15 Brčko | 2021/05/18 14:20 | Viktor Jovic v Nicolas Zanellato | 4-6,0-6 |
| ITF M15 Brčko | 2021/05/18 08:15 | Viktor Jovic v Michel Hopp | 2-6,6-3,10-5 |
| ITF M15 Monastir | 2021/04/26 13:30 | Viktor Jovic v Savva Polukhin | 2-6,3-6 |