Steven Moneke defeated Marc Sieber 7-5 6-1 in the Croatia F6 qualifying round on clay. The upset overturned the form book — Marc Sieber came in leading the head-to-head 2–0. Steven Moneke claimed a first win over Marc Sieber in three meetings, narrowing the head-to-head to 2–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2012-07-02 | Germany F8 | R32 | clay | Marc Sieber | 7-6(3) 6-2 |
| 2011-03-21 | Croatia F3 | R32 | clay | Marc Sieber | 3-6 6-2 6-1 |
Averages over each player's completed matches in the selected window. ATP, WTA & Challenger.