Marcello Wowk defeated Sebastien De Chaunac 1-6 6-3 6-4 in the Switzerland 1 Masters 2 round of 16 on clay. The upset overturned the form book — Sebastien De Chaunac came in leading the head-to-head 1–0. Marcello Wowk claimed a first win over Sebastien De Chaunac in two meetings, narrowing the head-to-head to 1–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 1998-08-05 | Switzerland 1 Masters 1 | QF | clay | Sebastien De Chaunac | 6-7 6-4 6-2 |
Averages over each player's completed matches in the selected window. ATP, WTA & Challenger.