Yuichi Sugita defeated Jae Sung An 6-2 6-3 in the Thailand F4 qualifying round on hard. The upset overturned the form book — Jae Sung An came in leading the head-to-head 2–0. Yuichi Sugita claimed a first win over Jae Sung An in three meetings, narrowing the head-to-head to 2–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2009-10-12 | Japan F8 | R32 | hard | Jae Sung An | 6-4 6-1 |
| 2009-03-30 | Japan F3 | F | hard | Jae Sung An | 5-7 6-4 7-6(5) |
Averages over each player's completed matches in the selected window. ATP, WTA & Challenger.