Irina Spirlea defeated Arantxa Sanchez Vicario 7-6 6-1 in the WTA Tour Championships round of 16 on carpet. The upset overturned the form book — Arantxa Sanchez Vicario came in leading the head-to-head 3–2, defending last year's quarter-final. Irina Spirlea narrowed the head-to-head to 3–3.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 1999-05-24 | Roland Garros | R32 | clay | Arantxa Sanchez Vicario | 6-4 6-1 |
| 1999-04-19 | Cairo | F | clay | Arantxa Sanchez Vicario | 6-1 6-0 |
| 1997-10-06 | Filderstadt | QF | hard | Irina Spirlea | 7-5 6-4 |
| 1997-06-17 | Eastbourne | QF | grass | Arantxa Sanchez Vicario | 6-4 6-4 |
| 1997-03-07 | Indian Wells | SF | hard | Irina Spirlea | 4-6 6-3 6-3 |