| Kofu, Singles Qualifying W-WITF-JPN-02A | 2017/03/27 02:30 | So, Kumi v Kato, Kei | 2-6,6-7 |
| Kofu, Singles Qualifying W-WITF-JPN-02A | 2017/03/25 01:00 | Sakata, Kimika v Kato, Kei | 4-6,3-6 |
| Nishi-Tama, Singles W-WITF-JPN-01A | 2017/03/20 01:00 | Kato, Kei v Fujiwara, Rika | 3-6,0-6 |
| Nishi-Tama, Singles W-WITF-JPN-01A | 2017/03/19 01:00 | 高山千尋 高山千尋 v Kato, Kei | 1-6,2-6 |
| Yokohama, Singles Qualifying W-WITF-JPN-01B | 2017/03/06 04:00 | ミノコシ,マイ v Kato, Kei | 6-2,6-7,6-2 |
| ITF Women Hong Kong | 2016/12/24 02:00 | リュ,ミンヤン v Kato, Kei | 7-6,6-3 |
| ITF Women Hamamatsu | 2016/10/19 05:40 | Kato, Kei v アオヤマ・シュウコ | 2-6,0-6 |
| Makinohara, Singles Qualifying W-WITF-JPN-15A | 2016/10/13 00:30 | Kato, Kei v Lykina, Ksenia | 1-6,0-6 |
| Kofu, Singles Qualifying W-WITF-JPN-02A | 2017/03/27 02:30 | Fujioka, Nozomi v オオサカ,マリ | 0-6,3-6 |
| Kofu, Singles Qualifying W-WITF-JPN-02A | 2017/03/25 01:00 | 長船 香菜子 v オオサカ,マリ | 1-6,0-6 |
| Tampa, Singles W-WITF-USA-08A | 2017/03/18 15:40 | Larcherde Brito, Michelle v オオサカ,マリ | 3-6,7-5,6-4 |
| Tampa, Singles W-WITF-USA-08A | 2017/03/17 14:00 | レナータ・ザラズア v オオサカ,マリ | 1-6,0-6 |
| Tampa, Singles W-WITF-USA-08A | 2017/03/16 14:00 | オオサカ,マリ v Kramperova, Katerina | 7-6,6-4 |
| Tampa, Singles W-WITF-USA-08A | 2017/03/14 15:00 | Veronika Miroshnichenko v オオサカ,マリ | 2-6,1-6 |
| ITF Women Rancho Santa Fe Qual | 2017/02/19 17:00 | オオサカ,マリ v アシュリー クラッツァー | 6-7,3-6 |
| Surprise, Singles Qualifying W-WITF-USA-05A | 2017/02/14 16:00 | アナスタシア・ポタポワ v オオサカ,マリ | 6-1,7-5 |