| Cordenons, Italy | 08/15 13:10 | 26 | [236] Clezar, Guilherme v Pedro Cachin [260] | 6-2,6-4 | |
| Cordenons, Italy | 08/13 17:00 | 25 | [236] Clezar, Guilherme v Balzerani, Riccardo [472] | 6-2,7-5 | |
| Pullach, Germany | 08/07 16:35 | 25 | [149] Moraing, Mats v Clezar, Guilherme [221] | 6-2,3-6,6-3 | |
| Challenger Liberec | 07/30 10:30 | 25 | Goncalo Oliveira v Clezar, Guilherme | 7-6,6-2 | |
| Challenger - Prague | 07/27 11:00 | 27 | [264] Nedovyesov, Aleksandr v Clezar, Guilherme [192] | 6-4,7-6 | |
| Challenger - Prague | 07/26 12:35 | 26 | Clezar, Guilherme v van Rijthoven, Tim | 6-3,6-7,6-4 | |
| Challenger - Prague | 07/25 10:40 | 25 | [192] Clezar, Guilherme v Brands, Daniel [217] | 6-3,6-1 | |
| Wimbledon Qual | 06/25 11:15 | 44 | [129] Fabbiano, Thomas v Clezar, Guilherme [213] | 6-2,6-3 | |
| L'Aquila, Italie | 06/23 13:00 | 28 | [190] Facundo Bagnis v Clezar, Guilherme [213] | 6-3,5-7,7-6 | |
| L'Aquila, Italie | 06/22 13:00 | 27 | [213] Clezar, Guilherme v Quinzi, Gianluigi [216] | 6-3,1-6,7-6 | |
| L'Aquila, Italie | 06/20 10:05 | 26 | [291] Cuevas, Martin v Clezar, Guilherme [213] | 3-6,6-1,2-6 | |
| L'Aquila, Italie | 06/19 10:50 | 25 | [496] Riccardo Bonadio v Clezar, Guilherme [213] | 4-6,5-7 | |
| L'Aquila, Italie | 06/19 08:00 | - | Robredo, Tommy v Clezar, Guilherme | Cancelled | |
| Challenger Almaty | 06/14 05:00 | 27 | [218] Clezar, Guilherme v Yannick Hanfmann [114] | 3-6,2-6 | |
| Challenger Almaty | 06/13 07:55 | 26 | [187] Nikola Milojevic v Clezar, Guilherme [218] | 2-6,6-3,1-6 | |
| Challenger Almaty | 06/12 05:20 | 25 | [227] Goncalo Oliveira v Clezar, Guilherme [218] | 6-3,3-6,1-6 | |
| Shymkent 2, Kazakhstan | 06/05 04:00 | 25 | [471] Tung-Lin Wu v Clezar, Guilherme [231] | 7-5,6-4 | |
| Challenger Vicenza | 06/01 14:30 | 27 | [231] Clezar, Guilherme v Gian Marco Moroni [295] | 3-6,2-6 | |
| Challenger Vicenza | 05/31 12:30 | 26 | [231] Clezar, Guilherme v Quinzi, Gianluigi [204] | 6-4,6-3 | |
| Challenger Vicenza | 05/30 09:00 | 25 | [125] Lorenzo Sonego v Clezar, Guilherme [231] | 6-3,3-6,4-6 | |
| Challenger Vicenza Qual | 05/28 10:00 | 54 | [351] Gianluca Mager v Clezar, Guilherme [231] | 6-3,6-2 | |
| Challenger Vicenza Qual | 05/27 09:00 | 46 | Luca Giacomini v Clezar, Guilherme | 5-7,3-6 | |
| Challenger Vicenza Qual | 05/26 08:00 | 45 | [397] Reboul, Fabien v Clezar, Guilherme [231] | 2-6,4-6 | |
| French Open Qual | 05/21 09:15 | 44 | [114] Denis Kudla v Clezar, Guilherme [231] | 6-3,6-7,7-5 | |
| Challenger - Savannah | 05/04 15:25 | 27 | [240] Clezar, Guilherme v Hugo Dellien [158] | 7-5,4-6,6-7 | |
| Challenger - Savannah | 05/02 14:30 | 26 | [209] Lopez Perez v Clezar, Guilherme [240] | 6-0,6-7,4-6 | |
| Challenger - Savannah | 04/30 14:00 | 25 | [240] Clezar, Guilherme v Dominik Koepfer [243] | 6-2,6-3 | |
| Challenger - Tallahassee | 04/25 17:00 | 26 | [235] Clezar, Guilherme v Garin, Cristian [220] | 4-6,2-6 | |
| Challenger - Tallahassee | 04/24 18:55 | 25 | [235] Clezar, Guilherme v Arnaboldi, Andrea [234] | 6-2,6-4 | |
| Challenger - Sarasota | 04/20 16:00 | 27 | [241] Clezar, Guilherme v Opelka, Reilly [211] | 7-5,4-6,4-6 |