Stadium: Court 21 Round: 25 Ground: Hardcourt outdoor
| Challenger Sibiu | 2021/09/27 07:00 | Kai Wehnelt v Stefan Palosi | 6-7,7-6,2-6 |
| ITF M15 Sozopol | 2021/09/19 07:00 | Kai Wehnelt v Ryan James Storrie | 4-6,6-0,2-6 |
| ITF M15 Sozopol | 2021/09/18 07:00 | Kai Wehnelt v Martin Krumich | 6-4,6-2 |
| ITF M15 Sozopol | 2021/09/17 07:00 | Kai Wehnelt v Calin Manda | 4-6,6-4,6-1 |
| ITF M15 Sozopol | 2021/09/16 07:00 | Kai Wehnelt v Joshua Paris | 6-2,6-4 |
| ITF M15 Sozopol | 2021/09/14 09:00 | Kai Wehnelt v Zura Tkemaladze | 6-2,6-2 |
| ITF M25 Eupen | 2021/09/08 07:30 | Guy Den Heijer v Kai Wehnelt | 3-6,6-3,6-2 |
| ITF M25 Trier | 2021/08/26 11:00 | Quentin Folliot v Kai Wehnelt | 7-5,4-6,7-5 |
| ATP Sofia | 2021/09/26 11:05 | Pedro Martinez v Simon A Ivanov | 7-5,6-1 |
| ATP Nur-Sultan | 2021/09/19 06:00 | Simon A Ivanov v Dmitry Popko | 2-6,3-6 |
| ITF M15 Sozopol | 2021/09/16 08:00 | Simon A Ivanov v George Tsivadze | 7-6,6-0 |
| ITF M15 Sozopol | 2021/09/15 09:30 | Simon A Ivanov v Dragomir Draganov | 6-2,6-4 |
| ITF M15 Ulcinj | 2021/09/07 08:00 | Felix Gill v Simon A Ivanov | 6-3,5-7,7-6 |
| ITF M15 Ulcinj | 2021/09/01 13:30 | Antonio Cayetano March v Simon A Ivanov | 7-6,6-1 |
| ITF M25 Bacau | 2021/08/18 12:40 | Simon A Ivanov v Arthur Cazaux | 4-6,4-6 |
| ITF M25 Bacau | 2021/08/17 07:00 | Simon A Ivanov v Gheorghe Claudiu Schinteie | 6-3,6-1 |