Stadium: Court 5 Round: 25 Ground: Hardcourt outdoor
| ITF M25 Nakhon Si Thammarat | 2023/06/15 03:25 | Orel Kimhi v Daisuke Sumizawa | 6-1,6-3 |
| ITF M15 Nakhon Si Thammarat | 2023/06/07 03:30 | Daisuke Sumizawa v Maximus Jones | 1-6,2-6 |
| ITF M15 Karuizawa | 2023/06/01 00:30 | Sora Fukuda v Daisuke Sumizawa | 6-3,6-4 |
| ITF M15 Karuizawa | 2023/05/30 07:35 | Taketo Takamisawa v Daisuke Sumizawa | 2-6,4-6 |
| Challenger Busan | 2023/05/08 02:00 | Daisuke Sumizawa v Woobin Shin | 6-2,3-6,2-6 |
| Challenger Gwangju | 2023/04/30 04:10 | Daniel Masur v Daisuke Sumizawa | 6-0,6-4 |
| ITF M25 Kashiwa | 2023/04/06 01:30 | Daisuke Sumizawa v Yunseong Chung | 2-6,2-6 |
| ITF M25 Kashiwa | 2023/04/05 03:15 | Ryotaro Taguchi v Daisuke Sumizawa | 6-7,7-6,6-7 |
| ITF M25 Anseong | 2023/06/19 05:40 | Ko Suzuki v Hayeon Seong | 6-4,6-4 |
| ITF M25 Anseong | 2023/06/19 02:15 | Ko Suzuki v Min Seong Kim | 6-1,6-2 |
| ITF M25 Anseong | 2023/06/18 01:00 | Ko Suzuki v Ki Bum Kim | 6-2,6-4 |
| ITF M15 Karuizawa | 2023/06/01 00:30 | Kazuma Kawachi v Ko Suzuki | 6-2,1-6,7-5 |
| ITF M15 Karuizawa | 2023/05/31 01:00 | Ko Suzuki v Yamato Sueoka | 7-5,6-7,6-4 |
| ITF M15 Karuizawa | 2023/05/30 03:00 | Ko Suzuki v Yusuke Kusuhara | 7-6,4-6,10-8 |
| ITF M25 Kashiwa | 2023/04/02 00:30 | Ko Suzuki v Taiyo Yamanaka | 1-6,6-3,11-13 |
| ITF M25 Tsukuba | 2023/03/29 04:15 | Hiroki Moriya v Ko Suzuki | 6-3,6-1 |