Japan's Naomi Osaka claimed her first WTA victory, when she survived a match point to beat former U.S. Open champion Samantha Stosur in three sets in the first round of the Bank of the West Classic on Monday.
The 16-year-old Osaka is ranked 400th in the world and advanced through qualifying to reach the main draw at Stanford University.
She won three straight points to win the second-set tiebreaker and rallied from a 5-3 deficit in the third to win 4-6, 7-6 (9-7), 7-5 over the Australian, who is ranked 19th in the world.