German wild card Cedrik-Marcel Stebe celebrated his first victory on the ATP tour when he upset sixth-seeded Nikolay Davydenko of Russia 3-6, 6-1, 6-4 in the first round of the Mercedes Cup on Tuesday.
The 20-year-old German who comes from near Stuttgart lost his only other tour-level matches, in the first round at Halle and Wimbledon. Both were on grass.
Davydenko was twice a semifinalist in the clay-court tournament in Stuttgart.
Two Spaniards, Juan Carlos Ferrero and Pablo Andujar, also advanced, along with Lukasz Kubot of Poland.