| Challenger Columbus | 02/27 18:45 | 26 | [270] Clezar, Guilherme v Istomin, Denis [165] | 3-6,1-6 | |
| Challenger Columbus | 02/26 15:00 | 25 | [236] Jason Kubler v Clezar, Guilherme [270] | 6-2,6-7,4-6 | |
| Challenger Columbus | 02/25 15:00 | 24 | Boulais, Justin v Clezar, Guilherme | 4-6,2-6 | |
| Challenger - Morelos | 02/22 22:00 | 28 | [297] Clezar, Guilherme v Jurij Rodionov [230] | 6-3,2-6,4-6 | |
| Challenger - Morelos | 02/21 19:00 | 27 | [221] Daniel Altmaier v Clezar, Guilherme [297] | 6-3,6-7,4-6 | |
| Challenger - Morelos | 02/20 16:30 | 26 | [266] Quiroz, Roberto v Clezar, Guilherme [297] | 6-7,2-6 | |
| Challenger - Morelos | 02/19 21:30 | 25 | [297] Clezar, Guilherme v Ramkumar Ramanathan [179] | 7-6,4-6,6-4 | |
| Challenger - Morelos | 02/18 01:35 | 24 | [362] Hidalgo, Diego v Clezar, Guilherme [297] | 6-7,2-6 | |
| Challenger - Cleveland | 02/12 15:00 | 25 | [209] Ernesto Escobedo v Clezar, Guilherme [298] | 6-3,6-4 | |
| Challenger - Cleveland | 02/10 15:50 | 24 | [298] Clezar, Guilherme v Smith, John-Patrick [303] | 6-3,2-6,7-6 | |
| Challenger - Punta del Este | 02/01 00:00 | 27 | [328] Clezar, Guilherme v Thiago Monteiro [86] | 4-6,1-6 | |
| Challenger - Punta del Este | 01/30 20:30 | 26 | [119] Federico Coria v Clezar, Guilherme [328] | 5-7,6-4,5-7 | |
| Challenger - Punta del Este | 01/28 15:50 | 25 | [328] Clezar, Guilherme v Andrea Collarini [192] | 7-6,7-6 | |
| Challenger - Punta del Este | 01/27 15:50 | 24 | [328] Clezar, Guilherme v Pedro Cachin [366] | 6-4,7-6 | |
| Challenger Ortisei | 11/12 09:00 | 24 | [305] Clezar, Guilherme v Ignatik, Uladzimir [307] | 4-6,7-6,1-6 | |
| Montevideo, Uruguay | 11/07 17:00 | 26 | [205] Andrea Collarini v Clezar, Guilherme [318] | 6-3,6-4 | |
| Montevideo, Uruguay | 11/06 14:00 | 25 | [318] Clezar, Guilherme v Thiago Monteiro [88] | 7-6,6-7,6-3 | |
| Montevideo, Uruguay | 11/05 14:00 | 24 | [212] Alejandro Tabilo v Clezar, Guilherme [318] | 6-3,3-6,3-6 | |
| Challenger Guayaquil | 10/29 20:25 | 25 | [328] Clezar, Guilherme v Yannick Hanfmann [183] | 3-6,3-6 | |
| Challenger Guayaquil | 10/28 16:00 | 24 | [357] Nicolas Alvarez v Clezar, Guilherme [328] | 2-6,3-6 | |
| Challenger Lima | 10/24 00:00 | 25 | [161] Varillas, Juan Pablo v Clezar, Guilherme [322] | 7-5,6-2 | |
| Challenger Lima | 10/22 15:00 | 24 | [322] Clezar, Guilherme v Panta Herreros, Jorge Brian [494] | 6-2,6-3 | |
| Santo Domingo, Dominican Republic | 10/11 22:20 | 27 | [148] Federico Coria v Clezar, Guilherme [368] | 6-2,6-3 | |
| Santo Domingo, Dominican Republic | 10/10 23:00 | 26 | [208] Joao Menezes v Clezar, Guilherme [368] | 3-6,2-6 | |
| Santo Domingo, Dominican Republic | 10/10 02:50 | 25 | [368] Clezar, Guilherme v Mayer, Leonardo [94] | 6-3,1-6,7-6 | |
| Santo Domingo, Dominican Republic | 10/08 17:00 | 24 | [265] Juan Pablo Ficovich v Clezar, Guilherme [368] | 4-6,3-6 | |
| Challenger Campinas | 10/02 19:30 | 25 | [85] Hugo Dellien v Clezar, Guilherme [374] | 6-3,6-4 | |
| Challenger Campinas | 09/30 13:00 | 24 | [472] Jordan Correia Passos Do Carmo v Clezar, Guilherme [374] | 1-6,0-6 | |
| Challenger - Buenos Aires | 09/23 20:40 | 24 | [373] Clezar, Guilherme v Hernan Casanova [390] | 1-6,3-6 | |
| Challenger Banja Luka | 09/12 12:30 | 26 | [403] Clezar, Guilherme v Tallon Griekspoor [187] | 4-6,3-6 |