The top-seeded Davydenko defeated France's Florent Serra 6-1, 7-5 to advance in Moscow where he has won three out of the last four titles. The Russian, who beat Frenchman Paul-Henri Mathieu in last year's finale, next plays Spaniard Guillermo Garcia-Lopez.

Safin, a former world No. 1 who is seeded seventh, struggled to beat Israeli qualifier Noam Okun 7-6 (7-5), 3-6, 6-4 and next meets Frenchman Julien Benneteau.

In an upset, Uzbekistani qualifier Denis Istomin beat sixth-seeded Frenchman Michael Llodra 7-6 (7-2), 6-3. Eighth-seeded Serb Janko Tipsarevic survived a tough match against Russian wild card Alexandre Kudryavtsev, winning 4-6, 6-3, 7-6 (8-6).

Also Tuesday, Serbian Viktor Troicki beat Russian Evgeny Donskoy 6-1, 6-3; Benneteau beat Israeli Harel Levy 6-4, 6-3; Israeli Dudi Sela beat Romanian Victor Hanescu 6-3, 3-6, 6-2; and American Robby Ginepri beat Czech Jiri Vanek 6-3, 6-4.