Serena Williams defeated Arantxa Sanchez Vicario 6-2 6-4 in the Montreal semi-final on hard. The upset overturned the form book — Arantxa Sanchez Vicario came in leading the head-to-head 4–2, but Serena Williams had been the form player, winning 3 of their last 6 on hard. Serena Williams narrowed the head-to-head to 4–3.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 1999-09-27 | Grand Slam Cup | QF | hard | Serena Williams | 6-3 6-1 |
| 1999-08-09 | Manhattan Beach | QF | hard | Serena Williams | 6-2 6-3 |
| 1999-05-10 | Berlin | QF | grass | Arantxa Sanchez Vicario | 6-3 3-2 RET |
| 1998-06-15 | Eastbourne | QF | grass | Arantxa Sanchez Vicario | 4-6 6-4 6-4 |
| 1998-05-25 | Roland Garros | R16 | clay | Arantxa Sanchez Vicario | 4-6 7-5 6-3 |
| 1998-01-11 | Sydney | SF | hard | Arantxa Sanchez Vicario | 6-2 6-1 |
Averages over each player's completed matches in the selected window. ATP, WTA & Challenger.