Stadium: South Center Court Round: 25
| WTA Tokyo | 2018/09/15 01:00 | Mari Osaka v Antonia Lottner | 3-6,6-4,3-6 |
| ITF Women Montreux | 2018/09/07 13:00 | Kimberley Zimmermann v Mari Osaka | 7-5,6-4 |
| ITF Women Montreux | 2018/09/06 08:00 | Mari Osaka v Martina Trevisan | 6-3,6-2 |
| ITF Women Montreux | 2018/09/04 09:30 | Mari Osaka v Monika Kilnarova | 6-2,6-1 |
| ITF Women Budapest | 2018/08/25 12:40 | Mari Osaka v Maria Marfutina | 1-6,2-6 |
| ITF Women Braunschweig | 2018/08/22 09:00 | Anastasia Zarycka v Mari Osaka | 6-4,7-5 |
| ITF Women Porto | 2018/07/24 09:30 | Lisa Sabino v Mari Osaka | 6-2,6-1 |
| WTA Bucharest Qual | 2018/07/14 11:15 | Claire Liu v Mari Osaka | 6-0,3-6,6-4 |
| ITF Women Templeton | 2018/09/28 19:00 | Maria Sanchez v Madison Brengle | 3-6,1-6 |
| ITF Women Templeton | 2018/09/27 18:00 | Maria Sanchez v Ulrikke Eikeri | 6-3,6-4 |
| ITF Women Templeton | 2018/09/26 17:00 | Kristie Ahn v Maria Sanchez | 0-6,2-6 |
| WTA Chicago | 2018/09/02 15:00 | Robin Anderson v Maria Sanchez | 5-7,6-3,6-2 |
| WTA New Haven Qual | 2018/08/17 20:30 | Tamara Zidansek v Maria Sanchez | 7-5,7-6 |
| ITF Women Landisville Qual | 2018/08/06 14:00 | Maria Sanchez v Eri Hozumi | 5-7,5-7 |
| ITF Women Landisville Qual | 2018/08/05 16:20 | Nika Kukharchuk v Maria Sanchez | 5-7,3-6 |
| WTA San Jose Qual | 2018/07/29 19:45 | Maria Sanchez v Georgina Garcia-Perez | 6-7,6-7 |