| Challenger - Sarasota | 04/19 15:40 | 26 | [241] Clezar, Guilherme v King, Evan [192] | 7-6,3-6,6-2 | |
| Challenger - Sarasota | 04/17 14:00 | 25 | [113] Taro Daniel v Clezar, Guilherme [241] | 6-3,2-6,4-6 | |
| Challenger - Mexique | 04/10 17:00 | 25 | [308] Souza, Joao Olavo v Clezar, Guilherme [233] | 7-6,7-5 | |
| Coupe Davis | 04/08 01:40 | 28 | Giraldo, Santiago v Clezar, Guilherme | Cancelled | |
| Coupe Davis | 04/06 21:20 | 28 | [257] Daniel Elahi Galan v Clezar, Guilherme [234] | 3-6,6-2,6-1 | |
| Challenger - Santiago | 03/05 18:55 | 25 | Clezar, Guilherme v Bellucci, Thomaz | View | |
| Sao Paulo, Brazil | 03/01 18:05 | 26 | Albert Ramos-Vinolas v Clezar, Guilherme | 6-3,6-4 | |
| Sao Paulo, Brazil | 02/28 02:05 | 25 | Clezar, Guilherme v Thiago Monteiro | 6-3,1-6,7-5 | |
| Sao Paulo, Brazil, Qualifying | 02/25 16:10 | - | Pedro Sakamoto v Clezar, Guilherme | 2-6,1-6 | |
| Sao Paulo, Brazil, Qualifying | 02/24 19:20 | 26 | Fernando Yamacita v Clezar, Guilherme | 1-6,6-7 | |
| ATP Rio De Janeiro Qual | 02/17 18:00 | 26 | Clezar, Guilherme v Alessandro Giannessi | 7-6,4-6,3-6 | |
| ATP Buenos Aires Qual | 02/11 16:00 | - | Dutra Silva, Rogerio v Clezar, Guilherme | 7-6,7-6 | |
| ATP Buenos Aires Qual | 02/10 14:00 | 26 | Clezar, Guilherme v Renzo Olivo | 7-5,6-0 | |
| ATP Quito Qual | 02/03 16:00 | 26 | Escobar, Gonzalo v Clezar, Guilherme | 6-7,7-6,6-4 | |
| Newport Beach, USA | 01/22 19:55 | 25 | Clezar, Guilherme v Stefan Kozlov | 2-6,3-6 | |
| Challenger Rio De Janeiro | 11/24 19:00 | 27 | [125] Berlocq, Carlos v Clezar, Guilherme [222] | 7-5,6-1 | |
| Challenger Rio De Janeiro | 11/23 14:00 | 26 | [338] Lindell, Christian v Clezar, Guilherme [222] | 3-6,0-6 | |
| Challenger Rio De Janeiro | 11/21 18:00 | 25 | [222] Clezar, Guilherme v Goncalo Oliveira [212] | 3-6,6-3,6-3 | |
| Challenger Santiago 2 | 11/14 22:00 | 25 | [222] Clezar, Guilherme v Gonzalo Lama [452] | 4-6,6-2,3-6 | |
| Montevideo, Uruguay | 11/08 17:00 | 26 | [97] Nicolas Kicker v Clezar, Guilherme [228] | 6-3,6-1 | |
| Montevideo, Uruguay | 11/06 21:55 | 25 | [166] Balazs, Attila v Clezar, Guilherme [228] | 6-7,6-7 | |
| Challenger Lima | 10/24 15:30 | 25 | [225] Rola, Blaz v Clezar, Guilherme [200] | 7-6,6-0 | |
| Cali, Colombia | 10/21 16:00 | 29 | [232] Clezar, Guilherme v Delbonis, Federico [69] | 6-7,5-7 | |
| Cali, Colombia | 10/20 20:30 | 28 | [184] Martin, Andrej v Clezar, Guilherme [232] | 6-7,3-6 | |
| Cali, Colombia | 10/20 00:00 | 27 | [232] Clezar, Guilherme v Gonzalez, Alejandro [436] | 6-4,6-1 | |
| Cali, Colombia | 10/18 18:05 | 26 | [232] Clezar, Guilherme v Garin, Cristian [197] | 7-5,7-6 | |
| Cali, Colombia | 10/16 19:10 | 25 | Estrella Burgos, Victor v Clezar, Guilherme | 5-7,5-7 | |
| Challenger - Buenos Aires | 10/10 14:00 | 25 | Clezar, Guilherme v Linzer, Michael | 3-6,7-6,3-6 | |
| Challenger Campinas | 10/05 16:40 | 26 | [146] Gastao Elias v Clezar, Guilherme [238] | 6-4,7-6 | |
| Challenger Campinas | 10/03 19:00 | 25 | [238] Clezar, Guilherme v Lindell, Christian [334] | 6-3,6-2 |