Davydenko, seeded first in this year's tournament, defeated Andrei Pavel, 6-3, 6-4. Pavel was coming off a runner-up result in last week's tournament in Umag.
Second-seeded Tommy Robredo needed a third set before advancing to the second round with a 6-4, 5-7, 6-1 win over Polish wild-card entry Lukasz Kubot.
But third-seeded Juan Ignacio Chela was routed by Sergio Roitman 6-1, 6-2 and No. 5-seed Agustin Calleri was ousted by Stefan Koubek 0-6, 7-6 (7-3), 7-5. Also, eighth-seeded Potito Starace retired while trailing Boris Pashanski 6-7 (4-7), 6-2, 3-1.
Notable deaths of 2014 [PHOTOS]