Masayuki Ando defeated Yong Il Yoon 7-6 6-3 in the Japan 1 Masters 1 round of 16 on hard. The upset overturned the form book — Yong Il Yoon came in leading the head-to-head 1–0. Masayuki Ando claimed a first win over Yong Il Yoon in two meetings, narrowing the head-to-head to 1–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 1999-06-07 | Japan 1 Masters 4 | QF | hard | Yong Il Yoon | 6-2 6-3 |
Averages over each player's completed matches in the selected window. ATP, WTA & Challenger.