Tasuku Iwami defeated Yaoki Ishii 6-2 6-3 in the Japan F3 round of 32 on hard. The upset overturned the form book — Yaoki Ishii came in leading the head-to-head 3–1. Tasuku Iwami narrowed the head-to-head to 3–2.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2009-06-22 | Japan F6 | QF | carpet | Yaoki Ishii | 7-6(3) 3-6 6-3 |
| 2005-09-05 | Japan F10 | R32 | hard | Tasuku Iwami | 6-2 6-3 |
| 2005-04-25 | Japan F3 | R16 | carpet | Yaoki Ishii | 7-5 6-1 |
| 1997-11-17 | Japan 2 Masters 2 | R16 | hard | Yaoki Ishii | 7-5 6-2 |