Sadik Kadir defeated Marc Sieber 6-3 6-4 in the Germany F12 round of 32 on clay. The upset overturned the form book — Marc Sieber came in leading the head-to-head 1–0. Sadik Kadir claimed a first win over Marc Sieber in two meetings, narrowing the head-to-head to 1–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2009-05-18 | Poland F1 | R32 | clay | Marc Sieber | 6-2 6-7(3) 6-2 |
Averages over each player's completed matches in the selected window. ATP, WTA & Challenger.