Marius Zay defeated Stefan Seifert 7-5 6-2 in the Germany F16 round of 32 on clay. The upset overturned the form book — Stefan Seifert came in leading the head-to-head 3–0. Marius Zay claimed a first win over Stefan Seifert in four meetings, narrowing the head-to-head to 3–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2009-10-05 | Germany F19 | R32 | hard | Stefan Seifert | 6-3 6-2 |
| 2007-10-15 | Germany F20 | R32 | hard | Stefan Seifert | 6-1 6-0 |
| 2006-07-24 | Germany F9A | R32 | clay | Stefan Seifert | 6-2 6-2 |
Averages over each player's completed matches in the selected window. ATP, WTA & Challenger.