Stadium: Center Court A Round: 29 Ground: Hardcourt outdoor
| ITF M25 Sapporo | 2022/09/02 01:00 | Shuichi Sekiguchi v Daisuke Sumizawa | 7-6,7-6 |
| 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 02:30 | Shuichi Sekiguchi v Jumpei Yamasaki | 6-4,6-3 |
| ITF M25 Sapporo | 2023/09/07 01:00 | Shuichi Sekiguchi v Chase Ferguson | 6-2,6-2 |
| ITF M25 Sapporo | 2023/09/05 04:20 | Shuichi Sekiguchi v Hiroki Sakagawa | 6-3,6-2 |
| Challenger Zhangjiagang | 2023/08/28 10:15 | Shuichi Sekiguchi v Jie Cui | 1-6,2-6 |
| Challenger Zhangjiagang | 2023/08/27 06:25 | Shuichi Sekiguchi v Francis Casey Alcantara | 7-5,6-3 |
| Challenger Zhuhai | 2023/08/22 07:00 | Dominik Palan v Shuichi Sekiguchi | 7-6,5-7,6-2 |
| Challenger Zhuhai | 2023/08/21 03:00 | Shuichi Sekiguchi v Markos Kalovelonis | 7-6,2-6,6-4 |
| ITF M25 Sapporo | 2023/09/09 01:55 | Sora Fukuda v Daisuke Sumizawa | 4-6,4-6 |
| ITF M25 Sapporo | 2023/09/08 04:45 | Daisuke Sumizawa v Ko Suzuki | 7-5,6-2 |
| ITF M25 Sapporo | 2023/09/07 01:00 | Tomohiro Masabayashi v Daisuke Sumizawa | 3-6,3-6 |
| ITF M25 Hong Kong | 2023/08/30 04:10 | Egor Gerasimov v Daisuke Sumizawa | 4-6,6-3,7-5 |
| ITF M25 Hong Kong | 2023/08/28 02:00 | Daisuke Sumizawa v David Agung Susanto | 6-2,6-2 |
| ITF M25 Hong Kong | 2023/08/27 02:30 | Daisuke Sumizawa v Pengyu Lu | 3-6,6-1,10-5 |
| ITF M15 Caloundra | 2023/08/04 04:20 | Daisuke Sumizawa v Luke Saville | 4-6,4-6 |
| ITF M15 Caloundra | 2023/08/03 00:00 | Daisuke Sumizawa v Jeremy Zhang | 6-2,6-1 |