Stadium: Stadium (Ct 9) Round: 25
| ITF Women Jackson | 2018/04/04 15:00 | Mari Osaka v Gaia Sanesi | 5-7,4-6 |
| ITF Women Wesley Chapel Qual | 2018/01/23 19:40 | Mari Osaka v Olga Ianchuk | 6-7,4-6 |
| ITF Women Orlando Qual | 2018/01/14 15:00 | Mari Osaka v Caitlin Whoriskey | 3-6,6-7 |
| ITF Women Daytona Beach | 2018/01/12 15:00 | Mari Osaka v Grace Min | 6-7,4-6 |
| ITF Women Daytona Beach | 2018/01/11 16:30 | Elena-Gabriela Ruse v Mari Osaka | 6-7,3-6 |
| ITF Women Daytona Beach | 2018/01/11 01:05 | Mari Osaka v Kyoka Okamura | 6-1,6-1 |
| WTA Honolulu Qual | 2017/11/19 22:45 | Mari Osaka v Haruka Kaji | 3-6,5-7 |
| WTA Limoges Qual | 2017/11/05 12:00 | Mari Osaka v Olga Saez Larra | 6-1,3-6,6-7 |
| ITF Women Jackson | 2018/04/06 15:00 | Whitney Osuigwe v Barbara Haas | 6-0,7-5 |
| ITF Women Jackson | 2018/04/05 16:55 | Sanaz Marand v Barbara Haas | 3-6,2-6 |
| ITF Women Jackson | 2018/04/04 17:05 | Rasheeda McAdoo v Barbara Haas | 7-6,5-7,6-7 |
| ITF Women Santa Margherita | 2018/03/22 16:40 | Anastasiya Vasylyeva v Barbara Haas | 6-0,6-3 |
| ITF Women Sao Paulo | 2018/03/03 14:00 | Julia Grabher v Barbara Haas | 6-2,6-7,6-3 |
| ITF Women Sao Paulo | 2018/03/02 16:00 | Andrea Gamiz v Barbara Haas | 2-6,6-4,6-7 |
| ITF Women Sao Paulo | 2018/03/01 14:00 | Katerina Stewart v Barbara Haas | 6-1,2-6,1-6 |
| ITF Women Sao Paulo | 2018/02/28 13:00 | Tara Moore v Barbara Haas | 6-7,4-6 |