Soderling fought back from a set down to secure victory over Federer
Sweden's Robin Soderling beat world number one Roger Federer for the first time to book his place in the final of the Capitala World Tennis Championship.
Soderling came from a set down to beat the Swiss for the first time in 13 attempts 6-7 (6-8) 7-6 (7-1) 6-2.
"I always said the more times I play him, the closer I'll get, and here I am today," said Soderling.
The 25-year-old will play Spain's Rafael Nadal in Saturday's final after he beat David Ferrer 7-6 (7-3) 6-3.
Nadal, who lost to Andy Murray in last year's final, added: "This is the perfect preparation for Doha and then the Australian Open."
Soderling, meanwhile, had earned his place in the semi-finals of the six-man tournament by beating Federer's fellow Swiss Stanislas Wawrinka on Thursday, while Federer had a bye.
But the 15-time Grand Slam champion started well, taking the opening set on a closely fought tie-break and then breaking Soderling in the opening game of the second set.
Soderling, however, broke back in game six before levelling matters in a one-sided tie-break and he broke Federer twice in the decider to wrap up victory.
"So far so good, but it's going to be a long season for sure, hopefully I'll get to play against Roger a few more times," added Soderling.
Federer reflected on a tough opening to his 2010 season, saying: "Obviously it's hard to start playing against him, but I had fun."