Britain's Katie Boulter reached her first WTA 500 final by beating American Emma Navarro in straight sets at the San Diego Open.

Boulter, 27, won 6-3 6-1 in 74 minutes to reach Sunday's final and will face Ukraine's Marta Kostyuk, who got past American Jessica Pegula 7-6 (7-4) 6-1.

The British number one and world number 49 dominated on her serve, winning more than 87% of first-serve points.

She had just two break points against her serve, saving both.

Boulter also had to deal with a rain delay before she could overcome the third seed, the world number 26.

"Today was one of those matches where everything just clicks," she said.

"I came on the court and started the first few games and I could feel the power that she had and the way she works and manoeuvres the ball. I knew I had to come up with something better."

WTA 500 events are so-called as they offer 500 ranking points to the winner. Boulter, who will reach her highest career ranking thanks to her performances in California, won her sole WTA Tour title to date last year at the Nottingham Open, a WTA 250 event.

For comparison, a Grand Slam champion gets 2,000 ranking points, and WTA Finals winners can earn up to 1,500 points.

Sunday's final will be the first career meeting between Boulter and Kostyuk, who came back from 5-1 down in the opening set to earn victory over top seed Pegula, her first win against a top-five player.