Yasufumi Yamamoto defeated Oh Hee Kwon 6-0 6-7 6-4 in the Japan 2 Masters 1 round of 32 on hard. The upset overturned the form book — Oh Hee Kwon came in leading the head-to-head 1–0. Yasufumi Yamamoto claimed a first win over Oh Hee Kwon in two meetings, narrowing the head-to-head to 1–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 1998-09-30 | Japan F3 | SF | carpet | Oh Hee Kwon | 6-3 6-4 |
Averages over each player's completed matches in the selected window. ATP, WTA & Challenger.