Masato Hatanaka defeated Arata Onozawa 4-6 6-3 6-0 in the Japan F2 round of 32 on hard. The upset overturned the form book — Arata Onozawa came in leading the head-to-head 2–0. Masato Hatanaka claimed a first win over Arata Onozawa in three meetings, narrowing the head-to-head to 2–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2008-03-17 | Japan F1 | R32 | hard | Arata Onozawa | 6-2 6-4 |
| 2007-10-15 | Japan F10 | R32 | hard | Arata Onozawa | 7-5 1-6 7-5 |
Averages over each player's completed matches in the selected window. ATP, WTA & Challenger.