Stadium: Indoor 6 Round: 25 Ground: Hardcourt outdoor
| ITF Women Kurume | 2017/05/17 01:00 | Okuno, Ayaka v Erina Hayashi | 6-7,0-6 |
| ITF Women Fukuoka | 2017/05/10 01:00 | Okuno, Ayaka v Erina Hayashi | 3-6,3-6 |
| ITF Women Toyota Qual | 2018/03/10 01:00 | Yoshitomi, Aiko v Erina Hayashi | 6-2,6-1 |
| Manacor (Mallorca), Singles Quali W-WITF-ESP-01A | 2018/02/26 10:30 | Eden Silva v Erina Hayashi | 6-2,6-3 |
| Manacor (Mallorca), Singles Quali W-WITF-ESP-01A | 2018/02/23 09:35 | Erina Hayashi v Isabella Shinikova | 2-6,7-5,1-6 |
| Manacor (Mallorca), Singles Quali W-WITF-ESP-01A | 2018/02/20 14:00 | Adrover Gallego, Isabel v Erina Hayashi | 6-1,0-6,2-6 |
| Manacor (Mallorca), Singles Quali W-WITF-ESP-01A | 2018/02/15 09:00 | Isabella Shinikova v Erina Hayashi | 4-6,6-1,6-3 |
| Manacor (Mallorca), Singles Quali W-WITF-ESP-01A | 2018/02/14 09:00 | Lopez Giese, Laura v Erina Hayashi | 6-7,2-6 |
| ITF Women Taipei | 2017/06/22 04:15 | Alexandra Bozovic v Erina Hayashi | 6-2,6-2 |
| ITF Women Taipei | 2017/06/20 01:30 | Chen, Pei Hsuan v Erina Hayashi | 5-7,6-1,3-6 |
| ITF Women Toyota Qual | 2018/03/10 01:00 | Okuno, Ayaka v Kyoka Okamura | 1-6,3-6 |
| Yokohama, Singles Qualifying W-WITF-JPN-01B | 2018/03/04 07:00 | Okuno, Ayaka v Ya-Hsuan Lee | 4-6,4-6 |
| Surprise, Singles Qualifying W-WITF-USA-05A | 2018/02/11 17:00 | Giuliana Olmos v Okuno, Ayaka | 6-2,1-6,6-2 |
| ITF Women Hong Kong | 2018/01/02 04:10 | Luksika Kumkhum v Okuno, Ayaka | 6-1,6-2 |
| ITF Women Toyota Qual | 2017/11/12 02:00 | Okuno, Ayaka v Ohya, Nozomi | 2-6,3-6 |
| ITF Women Shenzhen Qual | 2017/11/06 03:00 | Okuno, Ayaka v Zhuoma Ni Ma | 1-6,7-6,2-6 |
| Hamamatsu, Singles W-WITF-JPN-12A | 2017/10/18 01:50 | Kawasaki, Mitsumi v Okuno, Ayaka | 6-1,6-1 |
| Makinohara, Singles Qualifying W-WITF-JPN-15A | 2017/10/11 00:30 | Okuno, Ayaka v Nishimoto, Megumi | 3-6,0-6 |