Estadio: Quadra 2 Round: 25 Ground: Clay
| ATP Santiago | 2021/03/06 18:20 | Guilherme Clezar v Felipe Meligeni Rodrigues Alves | 4-6,2-6 |
| ATP Buenos Aires | 2021/02/28 14:00 | Guilherme Clezar v Francisco Cerundolo | 6-2,3-6,2-6 |
| ATP Buenos Aires | 2021/02/27 16:35 | Hernan Casanova v Guilherme Clezar | 6-1,3-6,3-6 |
| ATP Cordoba | 2021/02/20 21:05 | Guilherme Clezar v Renzo Olivo | 4-6,4-6 |
| Challenger de Concepción | 2021/02/15 16:35 | Guilherme Clezar v Tomas Barrios Vera | 2-6,2-6 |
| Challenger de Campinas | 2020/12/01 17:20 | Guilherme Clezar v Facundo Mena | 4-6,4-6 |
| Challenger de Lisboa | 2020/10/16 10:25 | Guilherme Clezar v Federico Gaio | 7-5,4-6,6-7 |
| Challenger de Lisboa | 2020/10/15 12:30 | Nuno Borges v Guilherme Clezar | 3-6,6-7 |
| Challenger de Sao Paulo | 2021/12/01 14:15 | Johan Nikles v Felipe Meligeni Rodrigues Alves | 7-6,2-6,1-6 |
| Challenger de Sao Paulo | 2021/11/30 12:30 | Johan Nikles v Kaichi Uchida | 6-7,7-6,6-0 |
| Challenger de Brasilia | 2021/11/22 16:00 | Johan Nikles v Juan Ignacio Londero | 4-6,4-6 |
| Challenger de Campinas | 2021/11/16 13:00 | Thiago Monteiro v Johan Nikles | 6-2,6-1 |
| Challenger de Campinas | 2021/11/14 14:00 | Mateus Alves v Johan Nikles | 4-6,2-6 |
| Challenger de Lima | 2021/10/02 18:50 | Johan Nikles v Hugo Dellien | 7-6,4-6,2-6 |
| Challenger de Lima | 2021/10/01 17:20 | Johan Nikles v Renzo Olivo | 6-3,6-1 |
| Challenger de Lima | 2021/09/29 17:05 | Matheus P De Almeida v Johan Nikles | 6-7,4-6 |