Estadio: Court 2 Round: 54 Ground: Clay
| ITF M25 Risskov/Aarhus | 2023/06/11 08:00 | Gustav Theilgaard v Nikolaj Katic | 3-6,2-6 |
| UTR Pro - Copenhage | 2023/06/02 13:17 | Gustav Theilgaard v Philip Hjorth | 6-7,4-6 |
| UTR Pro - Copenhage | 2023/05/31 07:30 | Gustav Theilgaard v Oliver Valentinsson | 6-4,6-4 |
| UTR Pro - Copenhage | 2023/05/30 06:00 | Gustav Theilgaard v Adam Kresina | 6-0,7-5 |
| UTR Pro - Copenhage | 2023/05/29 09:35 | Gustav Theilgaard v Adamantios Stavrakas | 6-3,3-6,6-1 |
| UTR Pro - Copenhage | 2023/05/28 08:52 | Gustav Theilgaard v Oskar Brostrom Poulsen | 6-4,6-1 |
| UTR Pro Tennis Series - Copenhage | 2021/06/20 11:00 | Jesper Klov Nilsson v Gustav Theilgaard | 3-6,0-3 |
| UTR Pro Tennis Series - Copenhage | 2021/06/19 11:30 | Gustav Theilgaard v Hugo Pierre | 6-4,7-5 |
| ITF M15 Kamen | 2023/06/26 10:00 | Aloys J W Van Baal v Ivan Sergeyev | 6-3,6-2 |
| UTR Pro Hilversum | 2023/06/10 07:30 | Sander Jong v Ivan Sergeyev | 6-2,6-0 |
| UTR Pro Hilversum | 2023/06/09 06:00 | Ivan Sergeyev v Victor Sklenka | 6-4,6-7,6-0 |
| UTR Pro Hilversum | 2023/06/07 07:30 | Ivan Sergeyev v Julian Cundom | 6-3,6-2 |
| UTR Pro Hilversum | 2023/06/06 06:00 | Ivan Sergeyev v Quentin Robert | 4-6,2-5 |
| UTR Pro Hilversum | 2023/06/05 07:30 | Guy Den Heijer v Ivan Sergeyev | 0-6,2-6 |
| UTR Pro Zadar | 2023/03/29 07:30 | Ivan Sergeyev v Duje Ajdukovic | 1-6,0-1 |
| UTR Pro Zadar | 2023/03/28 07:30 | Ivan Sergeyev v Oleg Prihodko | 6-4,3-6,0-6 |