Stadium: Court 1 Round: 29 Ground: Clay
| ITF M15 Castelo Branco | 2021/07/31 08:30 | Joao Lucas Reis da Silva v Soares Klier, Gilbert | 6-4,2-6,6-7 |
| ITF M25 Medellin | 2021/09/18 14:50 | Pedro Sakamoto v Soares Klier, Gilbert | 3-6,6-7 |
| ITF M25 Medellin | 2021/09/17 15:00 | Soares Klier, Gilbert v Kohen, Alan | 6-2,4-6,6-1 |
| ITF M25 Medellin | 2021/09/16 15:00 | Soares Klier, Gilbert v Gomez, Mateo | 6-3,6-3 |
| ITF M25 Medellin | 2021/09/14 18:05 | Soares Klier, Gilbert v Enrique Bogo | 6-1,6-2 |
| ITF M25 Poznan | 2021/08/25 10:00 | Harry Wendelken v Soares Klier, Gilbert | 3-6,6-4,6-2 |
| ITF M15 Lodz | 2021/08/21 08:00 | Soares Klier, Gilbert v Maciej Rajski | 4-6,6-7 |
| ITF M15 Lodz | 2021/08/20 10:15 | Daniel Michalski v Soares Klier, Gilbert | 6-4,3-6,3-6 |
| ITF M15 Lodz | 2021/08/19 10:00 | Tommaso Compagnucci v Soares Klier, Gilbert | 4-6,2-6 |
| ITF M25 Medellin | 2021/09/18 15:00 | Lopez Villasenor, Gerardo v Joao Lucas Reis da Silva | 2-6,6-7 |
| ITF M25 Medellin | 2021/09/17 14:50 | Juan Sebastian Gomez v Joao Lucas Reis da Silva | 1-6,4-6 |
| ITF M25 Medellin | 2021/09/16 16:25 | Daniel Antonio Nunez v Joao Lucas Reis da Silva | 5-7,4-6 |
| ITF M25 Medellin | 2021/09/14 19:40 | Johan A Rodriguez Rodriguez v Joao Lucas Reis da Silva | 3-6,1-6 |
| ITF M15 Ibague | 2021/09/07 15:40 | Joao Lucas Reis da Silva v Baker, Blu | 6-4,3-6,3-6 |
| ITF M15 Castelo Branco | 2021/07/31 08:30 | Joao Lucas Reis da Silva v Soares Klier, Gilbert | 6-4,2-6,6-7 |
| ITF M15 Castelo Branco | 2021/07/30 08:30 | Duarte Vale v Joao Lucas Reis da Silva | 7-6,4-6,5-7 |
| ITF M15 Castelo Branco | 2021/07/29 11:30 | Pedro Araujo v Joao Lucas Reis da Silva | 4-6,4-6 |