Sebastien De Chaunac defeated Marcello Wowk 6-7 6-4 6-2 in the Switzerland 1 Masters 1 qualifying round on clay. The upset overturned the form book — Marcello Wowk came in leading the head-to-head 1–0. Sebastien De Chaunac claimed a first win over Marcello Wowk in two meetings, narrowing the head-to-head to 1–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 1998-08-05 | Switzerland 1 Masters 2 | R16 | clay | Marcello Wowk | 1-6 6-3 6-4 |
Averages over each player's completed matches in the selected window. ATP, WTA & Challenger.