Kentaro Masuda defeated Tetsuya Chaen 6-1 2-6 6-3 in the Japan 2 Masters 1 round of 32 on hard. The upset overturned the form book — Tetsuya Chaen came in leading the head-to-head 3–0. Kentaro Masuda claimed a first win over Tetsuya Chaen in four meetings, narrowing the head-to-head to 3–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 1998-03-25 | Japan F2 | F | carpet | Tetsuya Chaen | 7-6 7-5 |
| 1997-11-17 | Japan 2 Masters 2 | SF | hard | Tetsuya Chaen | 6-3 3-6 6-1 |
| 1997-07-07 | Japan 1 Masters 4 | QF | hard | Tetsuya Chaen | 6-2 2-6 6-2 |
Averages over each player's completed matches in the selected window (1 vs 2). 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