Kai Chen Chang defeated Yoon Young Jeong 1-6 6-3 6-3 in the Manila 10K qualifying round on clay. The upset overturned the form book — Yoon Young Jeong came in leading the head-to-head 1–0. Kai Chen Chang claimed a first win over Yoon Young Jeong in two meetings, narrowing the head-to-head to 1–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2009-04-27 | Gimcheon 25K | R16 | hard | Yoon Young Jeong | 7-6(2) 1-6 6-1 |
Averages over each player's completed matches in the selected window. ATP, WTA & Challenger.