Yong Il Yoon defeated Takahiro Terachi 3-6 7-5 7-6 in the Japan F4 semi-final on carpet. The upset overturned the form book — Takahiro Terachi came in leading the head-to-head 3–2. Yong Il Yoon narrowed the head-to-head to 3–3.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2003-05-12 | Korea Rep F3 | F | hard | Takahiro Terachi | 6-0 7-5 |
| 2003-04-14 | Japan F2 | SF | hard | Takahiro Terachi | 6-0 7-6(5) |
| 2000-05-08 | Japan F4 | F | hard | Takahiro Terachi | 2-6 7-6(7) 6-1 |
| 1999-06-07 | Japan 1 Masters 3 | SF | hard | Yong Il Yoon | 3-6 6-1 6-4 |
| 1998-05-04 | China F1 | SF | hard | Yong Il Yoon | 6-4 6-1 |
Averages over each player's completed matches in the selected window (8 vs 11). 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. About