Soderling, the event's eighth seed, followed his upset of No. 1 seeded American Andy Roddick in Friday's quarterfinals with a 7-6 (7-2), 6-3 victory against fourth-seeded Radek Stepanek. He will be trying for his third career title Sunday.
Soderling, who lost the final in Rotterdam, Netherlands, last Sunday, controlled the match after the first set tiebreaker 7-2.
The 23-year-old, unseeded Darcis was a 4-6 6-1 6-4 winner against Soderling's countryman, Jonas Bjorkman, to advance to his second career final.
Sunday's Soderling-Darcis winner earns a first-place check of $163,750.