Davydenko had never previously beaten Roddick in five meetings
Nikolay Davydenko claimed a two-set victory over Andy Roddick to seal a showdown with Rafael Nadal in the final of the Sony Ericsson Open in Miami.
Roddick was unable to build on the form that saw him beat world number one Roger Federer in the quarter-finals as Davydenko won 7-6 (7-5) 6-2.
Nadal moved into the final after a straight-sets win over Tomas Berdych.
The world number two, looking for his first title since Stuttgart last July, won 7-6 (8-6) 6-2 in first semi-final.
Roddick looked poised to win the first set against Davydenko when he forced a mini-break to 4-3 in the tie-break.
But fourth seed Davydenko, 26, won the next two points on the American's serve and went on to close out the set.
Roddick, the 2004 winner, broke in the third game of the second set for a 2-1 lead.
But that was to be the last game he won as his opponent broke back and added two more breaks to take the match in one hour 47 minutes.
Davydenko, who will be the first Russian in the 24-year history of this hardcourt event to play in the final, admits he faces a huge test to beat Nadal for the title.
"He's physically so fit," Davydenko said. "It's amazing, he doesn't seem to care if he's playing a night session or a day session. He runs so much and fights so hard."
Nadal lost an early lead and needed seven break points to seal the first set but raced through the second.
Second seed Nadal has looked focused all week as he attempts to become the first Spaniard to win in Key Biscayne, but he struggled at times against Berdych.
Nadal looked on course for a routine first set when he broke in game eight but surprisingly failed to serve out, missing one set point and then another two in game 10.
Nadal finished in good form after struggling to seal the first set
It came down to a tie-break and this time Nadal squandered a 6-3 lead before Berdych handed him the initiative with a double-fault on set point number seven.
Nadal needed no further encouragement, breaking at the start of a second set in which he committed no unforced errors and won the final 12 points.
"I think I am playing this tournament very well and today was a great match too," said Nadal.
"The first set was tough, especially at the end, because I had a lot of chances.
"The beginning of the set was very important. I had to be very concentrated with my serve because it was very tough in the wind."
Berdych admitted that back-to-back Masters Series events in the heat of Indian Wells and Miami had taken their toll.
"He was playing really solid to take the first set and then I have to say I got a little bit tired," said the Czech.
"It was like my battery's gone. It's really too long to stay here in the States."