Naomi Osaka eased to a straight-sets victory over Daria Kasatkina to claim her maiden title at the Indian Wells Masters on Sunday.
Osaka thrashed world number one Simona Halep to set up an unlikely showdown with Kasatkina and the unseeded Japanese sensation ended a dream week with a 6-3 6-2 victory.
Kasatkina had beaten the likes of Caroline Wozniacki, Angelique Kerber and Venus Williams to reach the biggest final of her career, but fell short in the battle of the 20-year-olds.
The unseeded Osaka showed maturity beyond her years, becoming the youngest woman to claim the title since Ana Ivanovic a decade ago.
Both players looked nervy early in the biggest match of their careers, sloppy errors leading to breaks in the first two games.
They soon looked more assured, but the 20th seed gifted Osaka the opportunity to serve for opening set with a poor service game, which her opponent won with a rasping backhand winner.
Osaka grasped her opportunity, another powerful backhand sealing the opening set in 39 minutes on a sunny day in California.
Kasatkina paid the price for being too tentative at the start of the second, Osaka on a mission as she broke in clinical fashion and held to lead 2-0.
The world number 19 pumped her fist after holding to reduce the deficit to 2-1 with an ace, but Osaka was a double break up courtesy of a fierce forehand winner.
Osaka did not allow Kasatkina a scent of a way back, losing just four points on serve in the second set and claiming the title with a backhand volley.