Arata Onozawa defeated Keita Koyama 6-2 6-1 in the Japan F7 round of 16 on clay. The upset overturned the form book — Keita Koyama came in leading the head-to-head 2–1. Arata Onozawa narrowed the head-to-head to 2–2.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2014-03-24 | Japan F3 | R32 | hard | Keita Koyama | 6-3 6-4 |
| 2013-06-24 | Japan F7 | QF | clay | Arata Onozawa | 6-3 6-3 |
| 2012-06-18 | Japan F6 | R32 | grass | Keita Koyama | 6-3 7-6(2) |
Averages over each player's completed matches in the selected window (46 vs 1). ATP, WTA & Challenger.
Each player's serve crossed against the other's return, converted to expected hold of serve. Recent completed matches, ATP, WTA & Challenger. Small sample — read as indicative. About