Serena Williams beat third seed Lindsay Davenport 6-1 7-5 to progress to the final of the $1.3m WTA event in Charleston, South Carolina.
Williams, playing on clay for the first time this year, maintained her unbeaten record in 2003 in a one-sided contest against her American rival.
The world number one was untouchable in the first set winning 6-1 before taking a 3-1 lead in the second over Davenport, one of the few players on the circuit who can match her for sheer power.
But she then finally lost her serve and allowed Davenport to level at 4-4.
Williams stepped up the pace again and broke to lead 6-5. Davenport had two break points in the next game, but Williams aced her on both occasions.
Williams sent down another ace to reach match point and then finished it off with a crosscourt forehand winner.
Playing Williams on Sunday will be Belgium's Justine Henin-Hardenne, who beat Ashley Harkleroad 6-2 6-1.
Henin-Hardenne, ranked fourth in the world, used powerful serving and a relentless backhand to end Harkleroad's run.
The 17-year-old American beat three seeded players on her way to her first WTA Tour semi-final.
Harkleroad looked as if she might make it four wins over seeded players early on, taking the first game at love. But Henin-Hardenne, playing this event for the first time, soon gained control.