Stadium: Court 18 Round: 62 Ground: Clay
| ITF M15 Den Haag | 2019/07/02 12:55 | Guy Den Heijer v Joao Lucas Reis da Silva | 6-4,6-1 |
| ITF M15 Antalya | 2021/01/28 07:00 | Joao Lucas Reis da Silva v Charles Minc | 6-4,6-2 |
| Challenger Campinas | 2020/11/30 17:15 | Joao Lucas Reis da Silva v Facundo Bagnis | 7-6,4-6,4-6 |
| Challenger Sao Paulo | 2020/11/24 15:00 | Christian Lindell v Joao Lucas Reis da Silva | 6-2,4-6,6-3 |
| Challenger Sao Paulo | 2020/11/22 16:00 | Benjamin Lock v Joao Lucas Reis da Silva | 1-6,4-6 |
| Challenger Sao Paulo | 2020/11/21 17:45 | Paulo Knippling v Joao Lucas Reis da Silva | 0-6,1-6 |
| ITF M15 Quinta Do Lago | 2020/11/03 12:00 | Michael Geerts v Joao Lucas Reis da Silva | 7-6,7-5 |
| ITF M25 Vale Do Lobo | 2020/10/28 11:45 | Nikolas Sanchez Izquierdo v Joao Lucas Reis da Silva | 3-6,7-5,6-4 |
| ITF M25 Vale Do Lobo | 2020/10/27 10:30 | Joao Lucas Reis da Silva v Goncalo Falcao | 6-4,6-4 |
| ITF M15 Antalya | 2021/01/28 07:00 | Mark Tryakshin v Guy Den Heijer | 2-6,1-6 |
| ITF M15 Alkmaar | 2020/08/23 14:30 | Guy Den Heijer v Leon Hoeveler | 6-2,6-3 |
| ITF M15 Loule | 2020/03/12 14:05 | Evan Hoyt v Guy Den Heijer | 6-2,5-7,1-6 |
| ITF M15 Loule | 2020/03/10 13:25 | Alexis Boureau v Guy Den Heijer | 3-6,3-6 |
| ITF M15 Faro | 2020/03/05 12:00 | Tiago Cacao v Guy Den Heijer | 6-2,6-2 |
| ITF M15 Faro | 2020/03/04 14:20 | Guy Den Heijer v Afonso Salgado | 6-3,6-3 |
| ITF M15 Vale Do Lobo | 2020/02/27 12:20 | Guy Den Heijer v Kenny de Schepper | 1-6,2-6 |
| ITF M15 Vale Do Lobo | 2020/02/26 10:00 | Marco Bortolotti v Guy Den Heijer | 6-7,2-6 |