Anne Gaelle Sidot defeated Ai Sugiyama 6-3 6-4 in the Los Angeles round of 32 on hard. The upset overturned the form book — Ai Sugiyama came in leading the head-to-head 3–1. Anne Gaelle Sidot narrowed the head-to-head to 3–2.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 1999-08-16 | Canadian Open | R16 | hard | Anne Gaelle Sidot | 6-4 6-3 |
| 1999-03-05 | Indian Wells | R64 | hard | Ai Sugiyama | 2-6 6-2 7-5 |
| 1998-08-10 | Manhattan Beach | R32 | hard | Ai Sugiyama | 6-4 6-3 |
| 1996-12-30 | Hope Island | SF | hard | Ai Sugiyama | 6-2 6-4 |
Averages over each player's completed matches in the selected window. ATP, WTA & Challenger.