Stadium: Court 4 Round: 24 Ground: Hardcourt outdoor
| ITF Women Florence | 2018/10/20 17:55 | Katie Volynets v Osaka, Mari | 2-6,6-4,3-6 |
| ITF Women Toronto | 2018/10/31 15:20 | Andreescu, Bianca Vanessa v Osaka, Mari | 6-1,6-1 |
| ITF Women Florence | 2018/10/21 17:00 | Osaka, Mari v Andreescu, Bianca Vanessa | 4-6,6-2,3-6 |
| ITF Women Florence | 2018/10/20 17:55 | Katie Volynets v Osaka, Mari | 2-6,6-4,3-6 |
| ITF Women Florence | 2018/10/19 14:00 | Osaka, Mari v Goncalves, Paula Cristina | 5-7,6-4,6-1 |
| ITF Women Florence | 2018/10/18 14:00 | Ulrikke Eikeri v Osaka, Mari | 1-6,3-6 |
| ITF Women Florence | 2018/10/16 17:55 | Gleason, Quinn v Osaka, Mari | 1-6,6-7 |
| ITF Women Stockton | 2018/10/04 22:30 | Osaka, Mari v Robin Anderson | 5-7,4-6 |
| ITF Women Stockton | 2018/10/03 20:55 | Osaka, Mari v Sanchez, Maria | 6-1,6-3 |
| Newport Beach, USA | 2019/01/21 18:00 | Guarachi Mathison, Alexa v Katie Volynets | 6-4,4-6,3-6 |
| ITF W25 Daytona Beach | 2019/01/16 16:15 | Ylena In-Albon v Katie Volynets | 6-4,6-1 |
| ITF W25 Daytona Beach | 2019/01/15 14:30 | Katie Volynets v Marine Partaud | 7-5,6-2 |
| ITF W25 Daytona Beach | 2019/01/14 16:00 | Hailey Baptiste v Katie Volynets | 6-0,6-7,4-10 |
| ITF Women Norman | 2018/11/17 16:00 | Katie Volynets v Maria Camila Osorio Serrano | 4-6,2-6 |
| ITF Women Norman | 2018/11/16 16:30 | Katie Volynets v Imanishi, Miharu | 6-3,7-6 |
| ITF Women Norman | 2018/11/15 18:05 | Sophie Chang v Katie Volynets | 3-6,3-6 |
| ITF Women Norman | 2018/11/14 21:20 | Katie Volynets v Ksenia Laskutova | 6-4,6-1 |