Defending champion Maria Sharapova beat Russian compatriot Anna Chakvetadze 6-3, 6-2 to book a spot in the final of the $1.83-million Acura Classic.
Looking for her first title since winning in autumn 2006 at Linz, Austria, world No.2 and defending champion Sharapova played with purpose and poise, using five service breaks in the 69-minute victory.
Double Grand Slam champion Sharapova, 20, won in sunny and breezy conditions on the hard courts of La Costa Spa and Resort.
In the title match Sunday, Sharapova will face the winner of the other semi-final contest between Russian ninth-seed Elena Dementieva and Swiss lefthander Patty Schnyder, the number 11 seed.
"I do what I have to do," said Sharapova, who has played for months through a nagging shoulder injury, which doctors tell her cannot get worse.
"The first set was pretty competitive, and once I got that first break in the second I felt I was on cruise control. It looked a little too easy, and I went down a service game. But a match is a match."
At the start of the match, she felt less sharp than in her earlier wins this week at Carlsbad.
"I was making a lot of unforced errors off of the return. But other than that, (after the break) it's a good situation to be in," Sharapova said.
Chakvetadze had won 12 consecutive singles matches in the last three weeks, including titles at Cincinnati, Ohio and Stanford, California. She stands a career-high number six on the WTA ranking.
But the challenge against the top seed was too much of a mountain for a player who wore herself out in winning a marathon Friday night over Wimbledon champion Venus Williams, saving a match point in the second set.
Chakvetadze failed to repeat the effort against Sharapova and fell to 0-5 all-time against the reigning US Open champion.
"I felt very tired. Maria played very well and hit a lot of winners, but I couldn't run, and I could not play," said Chakvetadze.
"I was not able to fight today (Saturday) like I did against Venus. I did not have much time to recover. In the end, I got cramps on my left side, and I couldn't move as well. Even though I lost, it was a good tournament for me, anyway. I hoped to go further but am happy because I had some good wins, and I will try harder."