Issei Okamura defeated Seiya Nakanishi 6-1 6-1 in the M25 Sapporo 1 round of 32 on hard. Issei Okamura extended the head-to-head to 3–0.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2025-09-02 | M25 Sapporo 1 | Q16 | hard | Issei Okamura | 4-6 7-6(5) 10-8 |
| 2023-03-27 | M25 Tsukuba 1 | Q32 | hard | Issei Okamura | 6-2 6-4 |
Averages over each player's completed matches in the selected window. ATP, WTA & Challenger.