Issei Okamura defeated Seiya Nakanishi 4-6 7-6 10-8 in the M25 Sapporo 1 q16 on hard. Issei Okamura extended the head-to-head to 3–0.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2023-09-05 | M25 Sapporo 1 | R32 | hard | Issei Okamura | 6-1 6-1 |
| 2023-03-27 | M25 Tsukuba 1 | Q32 | hard | Issei Okamura | 6-2 6-4 |