Estadio: Court 10 Round: 62 Ground: Clay
| ITF M25 Gandia | 2021/07/18 07:00 | Denis Klok v Hans Albert Schubert | 6-3,6-2 |
| ITF M15 Sofía | 2021/07/07 07:00 | Denis Klok v Aleksandr Braynin | 4-6,3-6 |
| ITF M25 Belgrade | 2021/06/27 07:00 | Denis Klok v George Botezan | 3-6,1-6 |
| ITF 15 Antalya | 2021/04/28 11:40 | Francesco Maestrelli v Denis Klok | 1-6,6-2,6-1 |
| ITF 15 Antalya | 2021/04/27 07:00 | Denis Klok v Vladimir Korolev | 6-1,4-6,10-3 |
| ITF 15 Antalya | 2021/04/26 07:00 | Denis Klok v Vojtech Mares | 6-3,6-2 |
| ITF 15 Antalya | 2021/04/25 07:00 | Denis Klok v Vladislav Ivanov | 6-1,7-6 |
| ITF 15 Antalya | 2021/04/18 07:00 | Denis Klok v Noel Larwig | 5-7,0-6 |