Stadium: Campo 1 Round: 26 Ground: Clay
| Challenger Buenos Aires | 2017/03/15 14:00 | Guilherme Clezar v Gianluigi Quinzi | 2-6,5-7 |
| Challenger Caltanissetta | 2016/06/07 12:10 | Guilherme Clezar v Gianluigi Quinzi | 2-6,6-1,6-7 |
| Challenger Vicenza | 2018/05/30 09:00 | Lorenzo Sonego v Guilherme Clezar | 6-3,3-6,4-6 |
| Challenger Vicenza Qual | 2018/05/28 10:00 | Gianluca Mager v Guilherme Clezar | 6-3,6-2 |
| Challenger Vicenza Qual | 2018/05/27 09:00 | Luca Giacomini v Guilherme Clezar | 5-7,3-6 |
| Challenger Vicenza Qual | 2018/05/26 08:00 | Fabien Reboul v Guilherme Clezar | 2-6,4-6 |
| French Open Qual | 2018/05/21 09:15 | Denis Kudla v Guilherme Clezar | 6-3,6-7,7-5 |
| Challenger Savannah | 2018/05/04 15:25 | Guilherme Clezar v Hugo Dellien | 7-5,4-6,6-7 |
| Challenger Savannah | 2018/05/02 14:30 | Enrique Lopez-Perez v Guilherme Clezar | 6-0,6-7,4-6 |
| Challenger Savannah | 2018/04/30 14:00 | Guilherme Clezar v Dominik Koepfer | 6-2,6-3 |
| Challenger Vicenza | 2018/05/30 09:00 | Gianluca Mager v Gianluigi Quinzi | 2-6,3-6 |
| Challenger Mestre | 2018/05/27 13:00 | Gian Marco Moroni v Gianluigi Quinzi | 2-6,2-6 |
| Challenger Mestre | 2018/05/26 11:00 | Gianluigi Quinzi v Danilo Petrovic | 6-2,7-6 |
| Challenger Mestre | 2018/05/25 13:50 | Lorenzo Giustino v Gianluigi Quinzi | 6-2,6-7,3-6 |
| Challenger Mestre | 2018/05/23 10:15 | Federico Gaio v Gianluigi Quinzi | 6-7,3-6 |
| Challenger Rome | 2018/05/11 11:50 | Gianluigi Quinzi v Adam Pavlasek | 7-6,3-6,5-7 |
| Challenger Rome | 2018/05/10 11:00 | Gianluigi Quinzi v Rogerio Dutra Silva | 6-4,6-4 |
| Challenger Rome | 2018/05/09 10:25 | Ruben Bemelmans v Gianluigi Quinzi | 6-4,1-6,2-6 |