Swede Anders Jarryd won the tournament in 1993.
Davydenko fought back from 5-2 down in the first set, but Soderling took the tiebreaker after the Russian double-faulted. A break in the ninth game of the second set ensured victory for the third-seeded Soderling, who lost the 2008 final to Michael Llodra.
"It's always tough. He is the best returner on the whole tour," Soderling said. "I very happy to beat one of the best players in the world."