Toshiharu Kato defeated Tasuku Iwami 6-4 6-2 in the Japan F3 round of 32 on clay. The upset overturned the form book — Tasuku Iwami came in leading the head-to-head 3–1. Toshiharu Kato narrowed the head-to-head to 3–2.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2005-10-01 | Tokyo | Q32 | hard | Tasuku Iwami | 7-6(3) 6-1 |
| 2005-04-18 | Japan F2 | R32 | clay | Tasuku Iwami | 7-6(6) 6-3 |
| 2004-04-26 | Japan F3 | R16 | hard | Toshiharu Kato | 6-3 6-4 |
| 2001-10-08 | Hong Kong F2 | R16 | hard | Tasuku Iwami | 3-6 6-0 7-6(2) |
Averages over each player's completed matches in the selected window. ATP, WTA & Challenger.