Stadium: Court 2 Round: 25 Ground: Hardcourt outdoor
| ITF M25 Sapporo | 2023/09/15 00:55 | Naoki Nakagawa v Seita Watanabe | 6-3,6-2 |
| ITF M25 Sapporo | 2023/09/17 01:55 | Naoki Nakagawa v Kazuki Nishiwaki | 4-6,6-1,6-4 |
| ITF M25 Sapporo | 2023/09/16 03:55 | Naoki Nakagawa v Hayato Matsuoka | 6-2,6-2 |
| ITF M25 Sapporo | 2023/09/15 05:35 | Naoki Nakagawa v Koki Matsuda | 6-4,6-2 |
| ITF M25 Sapporo | 2023/09/15 00:55 | Naoki Nakagawa v Seita Watanabe | 6-3,6-2 |
| ITF M25 Sapporo | 2023/09/13 01:00 | Naoki Nakagawa v Yusuke Kusuhara | 6-2,7-6 |
| ITF M25 Sapporo | 2023/09/09 02:00 | Naoki Nakagawa v Shuichi Sekiguchi | 7-5,3-6,5-7 |
| ITF M25 Sapporo | 2023/09/08 01:00 | Naoki Nakagawa v Kokoro Isomura | 6-2,6-0 |
| ITF M25 Sapporo | 2023/09/07 00:55 | Naoki Nakagawa v Shunsuke Wakita | 4-6,6-2,6-0 |
| ITF M25 Takasaki | 2023/09/18 03:30 | Mitsuki Wei Kang Leong v Seita Watanabe | 4-6,4-6 |
| ITF M25 Sapporo | 2023/09/15 00:55 | Naoki Nakagawa v Seita Watanabe | 6-3,6-2 |
| ITF M25 Sapporo | 2023/09/13 03:00 | Seita Watanabe v Yuta Kikuchi | 6-1,6-3 |
| ITF M25 Sapporo | 2023/09/06 03:35 | Seita Watanabe v Tatsuma Ito | 6-4,4-6,4-6 |
| ITF M25 Tainan | 2023/08/23 04:20 | Ergi Kirkin v Seita Watanabe | 4-6,7-6,6-3 |
| ITF M25 Tainan | 2023/08/15 02:00 | Seita Watanabe v Takuya Kumasaka | 3-6,6-4,2-6 |
| ITF M25 Astana | 2023/08/03 10:50 | Khumoyun Sultanov v Seita Watanabe | 4-6,6-3,7-5 |
| ITF M25 Astana | 2023/08/02 10:25 | Seita Watanabe v Timur Maulenov | 3-6,6-3,6-2 |