Ai Yamamoto defeated Katherine Westbury 4-6 7-5 6-2 in the Nonthaburi 10K round of 32 on hard. The result followed the form book — Ai Yamamoto came in leading the head-to-head 1–0. Ai Yamamoto extended the head-to-head to 2–0.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2009-06-22 | Bangkok 10K | SF | hard | Ai Yamamoto | 1-6 6-4 7-5 |
Averages over each player's completed matches in the selected window. ATP, WTA & Challenger.