Joannette Kruger defeated Serena Williams 6-1 6-1 in the Oklahoma quarter-final on hard. The upset overturned the form book — Serena Williams came in leading the head-to-head 1–0. Joannette Kruger claimed a first win over Serena Williams in two meetings, narrowing the head-to-head to 1–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 1998-05-04 | Rome | R32 | clay | Serena Williams | 5-1 RET |
Each player's serve crossed against the other's return, converted to expected hold of serve. Recent completed matches, ATP, WTA & Challenger. Small sample — read as indicative. About
Averages over each player's completed matches in the selected window (1 vs 199). ATP, WTA & Challenger.