Stadium: Pista 4 Round: 26 Ground: Hardcourt outdoor
| Challenger Mallorca | 2021/09/01 17:50 | Kacper Zuk v Dimitar Kuzmanov | 3-6,4-6 |
| US Open | 2021/08/24 22:45 | Dimitar Kuzmanov v Marius Copil | 6-7,4-6 |
| Challenger Tampere | 2021/07/21 09:00 | Dimitar Kuzmanov v Kyrian Jacquet | 6-3,4-6,6-7 |
| Challenger Tampere | 2021/07/19 15:30 | Kimmer Coppejans v Dimitar Kuzmanov | 6-1,3-6,6-7 |
| Challenger Iasi | 2021/07/16 09:40 | Felipe Meligeni Rodrigues Alves v Dimitar Kuzmanov | 6-0,3-6,6-3 |
| Challenger Iasi | 2021/07/14 11:15 | Nicholas David Ionel v Dimitar Kuzmanov | 6-2,3-6,4-6 |
| Challenger Iasi | 2021/07/13 07:00 | Pedja Krstin v Dimitar Kuzmanov | 2-6,2-6 |
| Challenger Perugia | 2021/07/07 13:50 | Dimitar Kuzmanov v Nerman Fatic | 4-6,6-7 |
| Challenger Mallorca | 2021/09/01 18:40 | Johannes Haerteis v Lukas Lacko | 2-6,3-6 |
| US Open | 2021/08/25 16:15 | Lukas Lacko v Holger Rune | 4-6,4-6 |
| ATP Atlanta | 2021/07/24 19:25 | Jason Jung v Lukas Lacko | 6-4,6-7,6-3 |
| Challenger Cary | 2021/07/19 23:45 | Mikael Torpegaard v Lukas Lacko | 6-4,6-2 |
| ATP Newport | 2021/07/11 18:30 | Lukas Lacko v Brayden Schnur | 0-6,4-6 |
| Wimbledon | 2021/06/22 10:00 | Lukas Lacko v Nikola Milojevic | 4-6,4-6 |
| ATP Halle | 2021/06/17 12:00 | Lloyd Harris v Lukas Lacko | 6-3,7-6 |
| ATP Halle | 2021/06/15 09:00 | Guido Pella v Lukas Lacko | 7-6,5-7,1-6 |