| UTR Pro Kawaguchi | 2024/06/22 01:00 | Christopher Kosei Ono v Seiya Nakanishi | 7-6,3-6,3-6 |
| UTR Pro Kawaguchi | 2024/06/20 01:30 | Hikaru Shiraishi v Seiya Nakanishi | 6-4,4-6,7-5 |
| UTR Pro Kawaguchi | 2024/06/19 00:00 | Taiyo Kurata v Seiya Nakanishi | 3-6,4-6 |
| UTR Pro Kawaguchi | 2024/06/17 02:41 | Seiya Nakanishi v Payton Jim on | 6-0,6-3 |
| ITF M15 Harmon | 2024/06/03 00:00 | Geni Inoue v Seiya Nakanishi | 6-1,6-1 |
| ITF M15 Harmon | 2024/06/02 00:00 | Babji Siva Atturu v Seiya Nakanishi | 1-6,2-6 |
| UTR Pro Urayasu | 2024/05/11 00:00 | Yuki Mochizuki v Seiya Nakanishi | 6-4,6-4 |
| UTR Pro Urayasu | 2024/05/09 03:00 | Kazuki Saito v Seiya Nakanishi | 4-6,2-6 |
| UTR Pro Kawaguchi | 2024/06/20 00:00 | Kosuke Nakanishi v Ryota Tanuma | 3-6,1-6 |
| UTR Pro Kawaguchi | 2024/06/19 02:19 | Kosuke Nakanishi v Kohtaro Kuriyama | 6-4,6-7,3-6 |
| UTR Pro Kawaguchi | 2024/06/17 01:30 | Kotaro Mochizuki v Kosuke Nakanishi | 2-6,2-6 |