Home History
| UTR Pro Tennis Series - Mulheim | 2021/07/26 11:00 | Billy Harris v Mark Wallner | 7-6,7-6 |
| ITF - M15 Perugia | 2021/07/21 12:15 | Remy Bertola v Billy Harris | 6-3,4-6,6-4 |
| ITF - M15 L'Aquila | 2021/07/15 12:20 | Pablo Llamas Ruiz v Billy Harris | 6-4,6-4 |
| ITF - M15 L'Aquila | 2021/07/14 16:50 | Gian Marco Ortenzi v Billy Harris | 6-2,1-6,4-6 |
| ITF - M15 Almada | 2021/07/06 13:50 | Billy Harris v Francisco Rocha | 2-6,1-6 |
| ITF - M15 Antalya | 2021/07/01 08:35 | Nicolae Frunza v Billy Harris | 7-6,6-2 |
| ITF - M15 Antalya | 2021/06/29 06:30 | Billy Harris v Matias Zukas | 3-6,6-3,6-4 |
| ITF - M15 Antalya | 2021/06/23 13:40 | Billy Harris v Facundo Juarez | 2-6,1-6 |
Away History
| UTR Pro Tennis Series - Mulheim | 2021/07/26 11:00 | Guy Den Heijer v Tim Sandkaulen | 7-5,6-3 |
| ITF - M25 Marburg | 2021/07/07 10:50 | Aleksandre Metreveli v Guy Den Heijer | 6-3,1-6,6-2 |
| ITF - M25 Marburg | 2021/07/06 12:25 | Guy Den Heijer v Florian Broska | 6-3,7-6 |
| ITF - M25 Marburg | 2021/07/05 08:00 | Guy Den Heijer v Maximilian Homberg | 6-7,6-2,10-8 |
| ITF - M25 Haga | 2021/06/29 15:00 | Dayne Kelly v Guy Den Heijer | 6-1,6-4 |
| ITF - M25 Haga | 2021/06/28 09:40 | Guy Den Heijer v Max Van Nunen | 6-3,6-1 |
| ITF - M25 Haga | 2021/06/27 08:00 | Guy Den Heijer v Jing L Weng | 6-3,6-4 |
| ITF - M25 Alkmaar | 2021/06/23 09:00 | Kaichi Uchida v Guy Den Heijer | 7-6,6-3 |