Alan Mackin defeated Jan Weinzierl 6-3 7-5 in the Croatia 1 4 qualifying round on clay. The upset overturned the form book — Jan Weinzierl came in leading the head-to-head 1–0. Alan Mackin claimed a first win over Jan Weinzierl in two meetings, narrowing the head-to-head to 1–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2003-03-10 | Croatia 1 2 | QF | clay | Jan Weinzierl | 6-1 6-4 |
Averages over each player's completed matches in the selected window. ATP, WTA & Challenger.