Hiromasa Oku defeated Katsuki Nagao 7-6 7-6 in the Japan F5 round of 16 on clay. The result followed the form book — Hiromasa Oku came in leading the head-to-head 1–0. Hiromasa Oku extended the head-to-head to 2–0.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2016-04-04 | Japan F5 | R32 | hard | Hiromasa Oku | 7-6(0) 5-7 6-1 |
Averages over each player's completed matches in the selected window. ATP, WTA & Challenger.