| ITF M25 Lajeado | 11/25 21:40 | 27 | Nicolas Zanellato v Clezar, Guilherme | 6-2,7-5 | |
| ITF M25 Lajeado | 11/24 21:25 | 26 | Enrique Bogo v Clezar, Guilherme | 5-7,0-6 | |
| ITF M25 Lajeado | 11/23 13:00 | 25 | Clezar, Guilherme v Huertas Del Pino Cordova, Arklon | 7-6,6-3 | |
| Challenger Rio De Janeiro | 12/14 13:00 | 25 | [313] Genaro Alberto Olivieri v Clezar, Guilherme [431] | 5-7,6-4,6-3 | |
| Challenger - Florianopolis | 12/06 19:00 | 25 | [427] Clezar, Guilherme v Johan Nikles [349] | 3-6,7-6,2-6 | |
| ATP - Santiago | 03/06 18:20 | 14 | [279] Clezar, Guilherme v Felipe M R Alves [236] | 4-6,2-6 | |
| ATP - Buenos Aires | 02/28 14:00 | 15 | [278] Clezar, Guilherme v Francisco Cerundolo [135] | 6-2,3-6,2-6 | |
| ATP - Buenos Aires | 02/27 16:35 | 14 | [369] Hernan Casanova v Clezar, Guilherme [278] | 6-1,3-6,3-6 | |
| ATP - Cordoba | 02/20 21:05 | 14 | [272] Clezar, Guilherme v Renzo Olivo [216] | 4-6,4-6 | |
| Challenger - Concepcion | 02/15 16:35 | 25 | [272] Clezar, Guilherme v Marcelo Tomas Barrios Vera [260] | 2-6,2-6 | |
| Challenger Campinas | 12/01 17:20 | 25 | [270] Clezar, Guilherme v Facundo Mena [238] | 4-6,4-6 | |
| Challenger Cary | 11/10 16:00 | 25 | [84] Thiago Monteiro v Clezar, Guilherme [268] | Retired | |
| Lisbon, Portugal | 10/16 10:25 | 27 | [270] Clezar, Guilherme v Federico Gaio [136] | 7-5,4-6,6-7 | |
| Lisbon, Portugal | 10/15 12:30 | 26 | [500] Nuno Borges v Clezar, Guilherme [270] | 3-6,6-7 | |
| Lisbon, Portugal | 10/13 09:00 | 25 | [206] Maxime Janvier v Clezar, Guilherme [270] | 6-7,2-6 | |
| Lisbon, Portugal | 10/11 10:30 | 164 | [263] Clezar, Guilherme v Orlando Luz [309] | 6-4,6-3 | |
| Lisbon, Portugal | 10/10 11:30 | 64 | Clezar, Guilherme v Monteiro, Joao | 6-7,6-4,6-1 | |
| Challenger - Barcelone | 10/03 13:10 | 26 | [201] Brandon Nakashima v Clezar, Guilherme [263] | 6-2,6-2 | |
| Challenger - Split | 09/27 08:00 | 164 | [273] Clezar, Guilherme v Barrios Vera, Marcelo Tomas [284] | 2-6,3-6 | |
| Challenger - Split | 09/26 13:55 | 64 | Clezar, Guilherme v Kekez, Duje | 6-2,6-3 | |
| Forli 6, Italy | 09/24 09:55 | 27 | [273] Clezar, Guilherme v Andrea Pellegrino [343] | 4-6,2-6 | |
| Forli 6, Italy | 09/23 10:45 | 26 | [98] Federico Coria v Clezar, Guilherme [273] | 6-7,7-6,4-6 | |
| Forli 6, Italy | 09/21 08:00 | 25 | [273] Clezar, Guilherme v Bachinger, Matthias [272] | 7-6,3-6,6-3 | |
| ITF M25 Plaisir | 09/18 11:00 | 27 | Igor Sijsling v Clezar, Guilherme | 6-4,6-4 | |
| ITF M25 Plaisir | 09/17 10:20 | 26 | Valentin Royer v Clezar, Guilherme | 7-6,6-7,4-6 | |
| ITF M25 Plaisir | 09/16 12:10 | 25 | Alexis Gautier v Clezar, Guilherme | 4-6,4-6 | |
| Monterrey, Mexico | 03/05 20:30 | 26 | [271] Clezar, Guilherme v King, Kevin [306] | 6-7,6-4,4-6 | |
| Monterrey, Mexico | 03/04 17:00 | 25 | [103] Federico Coria v Clezar, Guilherme [271] | 1-6,7-6,6-7 | |
| Monterrey, Mexico | 03/02 20:00 | 24 | [426] Nicolas Mejia v Clezar, Guilherme [271] | 1-6,4-6 | |
| Challenger Columbus | 02/27 18:45 | 26 | [270] Clezar, Guilherme v Istomin, Denis [165] | 3-6,1-6 |