Wei Ju Chen defeated Yasufumi Yamamoto 6-4 6-3 in the Japan Masters 3 round of 32 on hard. The upset overturned the form book — Yasufumi Yamamoto came in leading the head-to-head 3–0. Wei Ju Chen claimed a first win over Yasufumi Yamamoto in four meetings, narrowing the head-to-head to 3–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 1998-10-07 | Japan F4 | R32 | carpet | Yasufumi Yamamoto | 6-3 7-6 |
| 1998-09-30 | Japan F3 | R16 | carpet | Yasufumi Yamamoto | 6-3 7-6 |
| 1997-11-17 | Japan 2 Masters 2 | QF | hard | Yasufumi Yamamoto | 5-7 6-4 6-1 |
Averages over each player's completed matches in the selected window. ATP, WTA & Challenger.