Stadium: Center Court A Round: 25 Ground: Hardcourt outdoor
| ITF M15 Santo Domingo | 2023/06/21 13:30 | Tauheed Browning v Seita Watanabe | 7-6,0-6,7-5 |
| ITF M15 Karuizawa | 2023/05/31 01:00 | Jumpei Yamasaki v Seita Watanabe | 6-4,6-4 |
| UTR Pro Miki | 2023/02/12 02:00 | Tomohiro Masabayashi v Seita Watanabe | 4-6,1-5 |
| UTR Pro Miki | 2023/02/11 03:30 | Yuichiro Inui v Seita Watanabe | 6-7,6-7 |
| UTR Pro Miki | 2023/02/10 04:30 | Ren Nakamura v Seita Watanabe | 5-7,2-6 |
| UTR Pro Miki | 2023/02/09 03:30 | Kosuke Shibano v Seita Watanabe | 2-6,1-6 |
| UTR Pro Miki | 2023/02/08 03:30 | Ryohei Takase v Seita Watanabe | 2-6,1-5 |
| UTR Pro Miki | 2023/02/06 03:30 | Ryotaro Taguchi v Seita Watanabe | 6-2,6-7,7-6 |
| ITF M15 Karuizawa | 2023/06/04 02:00 | Yuta Kawahashi v Tatsuma Ito | 7-5,6-2 |
| ITF M15 Karuizawa | 2023/06/03 07:00 | Sora Fukuda v Tatsuma Ito | 6-7,6-7 |
| ITF M15 Karuizawa | 2023/06/03 03:30 | Kazuma Kawachi v Tatsuma Ito | 1-6,4-6 |
| ITF M15 Karuizawa | 2023/06/01 03:20 | Preston Brown v Tatsuma Ito | 3-6,0-6 |
| ITF M15 Karuizawa | 2023/05/31 03:35 | Seonyong Han v Tatsuma Ito | 6-7,3-6 |
| Challenger Busan | 2023/05/08 03:40 | Yuki Mochizuki v Tatsuma Ito | 6-4,4-6,6-2 |
| Challenger Busan | 2023/05/07 02:30 | Tatsuma Ito v Mukund Sasikumar | 5-7,6-4,6-4 |
| Challenger Gwangju | 2023/05/01 01:30 | Tatsuma Ito v Peter Gojowczyk | 4-6,4-6 |