Stadium: Court 5 Round: 44 Ground: Clay
| ITF Chile F2 | 2018/11/18 16:00 | Oscar Gabriel Ortiz v Rodrigo Echavarria | 4-6,3-6 |
| ITF Chile F2 | 2018/11/17 16:00 | Oscar Gabriel Ortiz v Karl W W Mac-Leay | 6-1,6-3 |
| ITF Argentina F9 | 2018/11/13 12:30 | Guido Ivan Justo v Oscar Gabriel Ortiz | 1-6,6-3,6-4 |
| ITF Argentina F8 | 2018/11/04 13:00 | Oscar Gabriel Ortiz v Santiago Besada | 2-6,1-6 |
| ITF Argentina F8 | 2018/11/03 13:00 | Aliaksandr Bulitski v Oscar Gabriel Ortiz | 6-2,1-6,3-6 |
| ITF Argentina F7 | 2018/10/30 17:00 | Oscar Gabriel Ortiz v Juan Manuel Cerundolo | 6-3,2-6,1-6 |
| ITF Argentina F7 | 2018/10/29 17:30 | Oscar Gabriel Ortiz v Ramiro Pioli Tizon | 1-6,6-4,6-1 |
| ITF Argentina F7 | 2018/10/28 15:30 | Francisco Comesana v Oscar Gabriel Ortiz | 4-6,3-6 |
| ITF Chile F2 | 2018/11/17 16:00 | Oscar Matias Leiva Biason v Mateo Berne | 6-3,3-6,3-6 |
| ITF Chile F1 | 2018/11/12 13:00 | Oscar Matias Leiva Biason v Federico Juan Aguilar | 1-6,3-6 |
| ITF Belgium F7 Qual | 2018/08/05 08:00 | Nico Mertens v Oscar Matias Leiva Biason | 6-1,6-0 |
| ITF Belgium F7 Qual | 2018/08/04 07:30 | Oscar Matias Leiva Biason v Javier A V. Meza | 6-0,6-0 |
| ITF Belgium F6 Qual | 2018/07/28 09:30 | Amaury Delmas v Oscar Matias Leiva Biason | 6-0,6-3 |
| ITF Germany F9 | 2018/07/22 08:00 | Oscar Matias Leiva Biason v Moritz Dettinger | 2-6,1-6 |
| ITF Belgium F4 | 2018/07/14 07:00 | Javier Naser v Oscar Matias Leiva Biason | 6-2,6-0 |
| ITF Germany F7 | 2018/07/09 08:00 | Andres Urrea v Oscar Matias Leiva Biason | 7-6,6-2 |