Stadium: Campo 1 Round: 54 Ground: Clay
| Challenger Caltanissetta Qual | 2018/06/10 12:10 | Joao Souza v Claudio Fortuna | 7-6,6-2 |
| Challenger Caltanissetta Qual | 2018/06/09 12:05 | Joao Souza v Fausto Tabacco | 6-2,6-2 |
| Challenger Guadalajara | 2018/04/17 20:15 | Joao Souza v Gonzalo Escobar | 6-2,3-6,5-7 |
| Challenger Guadalajara Qual | 2018/04/16 17:00 | Alejandro Gonzalez v Joao Souza | 4-6,6-0,3-6 |
| Challenger Guadalajara Qual | 2018/04/15 17:40 | Lloyd Glasspool v Joao Souza | 6-3,6-7,6-7 |
| Challenger Guadalajara Qual | 2018/04/14 19:05 | Raul-Isaias Rosas-Zarur v Joao Souza | 2-6,0-6 |
| Challenger - Mexico City | 2018/04/11 21:05 | Joao Souza v Adrian Menendez-Maceiras | 4-6,6-2,3-6 |
| Challenger - Mexico City | 2018/04/10 17:00 | Joao Souza v Guilherme Clezar | 7-6,7-5 |
| Challenger Caltanissetta Qual | 2018/06/10 11:30 | Marc Sieber v Pawel Juszczak | 6-0,6-1 |
| Challenger Caltanissetta Qual | 2018/06/09 13:25 | Mikhail Balmashev v Marc Sieber | 0-6,1-6 |
| Challenger Prostejov Qual | 2018/06/03 15:25 | Marc Sieber v Jan Satral | 6-4,3-6,4-6 |
| Challenger Prostejov Qual | 2018/06/03 09:45 | Pavel Nejedly v Marc Sieber | 1-6,5-7 |
| ITF Hungary F2 | 2018/05/18 08:00 | Mate Valkusz v Marc Sieber | 6-1,6-1 |
| ITF Hungary F2 | 2018/05/17 14:55 | Emil Ruusuvuori v Marc Sieber | 2-6,3-6 |
| ITF Hungary F2 | 2018/05/16 10:10 | Gabor Borsos v Marc Sieber | 1-6,7-6,1-6 |
| ITF Hungary F2 | 2018/05/15 12:30 | David Szintai v Marc Sieber | 4-6,3-6 |