Victoria Azarenka of Belarus advanced to her first major final by defeating Russian eighth seed Svetlana Kuznetsova 6-3, 2-6, 7-5 at the WTA and ATP hardcourt tournament Miami.
The 19-year-old 11th seed will meet the winner of a later semi-final that pits world number one Serena Williams, the reigning US and Australian Open champion, against sister Venus, the reigning Wimbledon champion.
Azarenka connected on 63 percent of her first serves for her first career victory over Kuznetsova, while her Russian rival committed 46 unforced errors.
"It's the biggest moment in my career," said Azarenka, who reached the semi-finals last month at Indian Wells.
"It feels great that all the work I've been doing is paying off. I was just trying to play every point from the beginning to the end."
Azarenka gave up an early service break in the first set, but won the next four games to pocket the set.
Kuznetsova raced to a 5-1 lead en route to leveling the match at one set apiece, but Azarenka broke Kuznetsova in the first game of the third set to gain the upper hand.
Azarenka missed her first opportunity to serve out the match, Kuznetsova saving one match point then breaking serve courtesy of an Azarenka double fault.
But Azarenka broke Kuznetsova in the next game, and sealed the victory on her third match point after two hours and 40 minutes played in sweltering heat.