Reginald Willems defeated Aleksander Mierzwinski 6-3 6-3 in the Belgium Masters 1 round of 16 on clay. The upset overturned the form book — Aleksander Mierzwinski came in leading the head-to-head 1–0, but Reginald Willems had been the form player, winning 4 of their last 6 on clay. Reginald Willems claimed a first win over Aleksander Mierzwinski in two meetings, narrowing the head-to-head to 1–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 1997-10-04 | France 6 Masters 3 | R32 | hard | Aleksander Mierzwinski | 6-4 7-6 |
Averages over each player's completed matches in the selected window. ATP, WTA & Challenger.