Kimberly Po Messerli defeated Ai Sugiyama 6-3 6-1 in the Stanford round of 16 on hard. The upset overturned the form book — Ai Sugiyama came in leading the head-to-head 2–1, but Kimberly Po Messerli had been the form player, winning 1 of their last 4 on hard. Kimberly Po Messerli narrowed the head-to-head to 2–2.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 1997-06-17 | Eastbourne | R16 | grass | Ai Sugiyama | 6-3 6-1 |
| 1997-04-14 | Tokyo | SF | hard | Ai Sugiyama | 5-7 6-4 6-1 |
| 1997-01-13 | Australian Open | R64 | hard | Kimberly Po Messerli | 6-0 4-6 6-3 |
Averages over each player's completed matches in the selected window. ATP, WTA & Challenger.