Yaoki Ishii defeated Tetsuya Chaen 6-0 6-2 in the China F1 qualifying round on hard. The result followed the form book — Yaoki Ishii came in leading the head-to-head 3–2. Yaoki Ishii extended the head-to-head to 4–2.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2008-06-30 | Japan F7 | R16 | hard | Yaoki Ishii | 6-4 6-1 |
| 2006-04-17 | Japan F2 | SF | carpet | Tetsuya Chaen | 6-2 3-6 6-4 |
| 2005-05-23 | Japan F4 | R16 | hard | Yaoki Ishii | 3-6 6-1 7-6(6) |
| 1998-03-25 | Japan F2 | SF | carpet | Tetsuya Chaen | 6-4 6-3 |
| 1997-11-17 | Japan 2 Masters 1 | QF | hard | Yaoki Ishii | 7-5 6-4 |