Naomi Osaka climbed two places to No. 4 in the latest WTA rankings released Monday, equaling the highest-ever standing by a Japanese player.
The 20-year-old — who was born in Osaka and raised in the United States by her Japanese mother and Haitian father — started the year as No. 68 but soared up the rankings with titles at Indian Wells in March and the U.S. Open last month.
She finished runner-up at the Toray Pan Pacific Open in Tokyo late last month and reached the semifinals of the China Open which concluded Sunday.
Two other Japanese players have previously reached world No. 4: Kimiko Date, in 1995, and Kei Nishikori, who most recently held the rank in March last year.
The top three players remain unchanged, with Romania's Simona Halep holding onto the No. 1 position, followed by Caroline Wozniacki of Denmark and Angelique Kerber of Germany.
Earlier this month, Osaka qualified for the season-ending WTA Finals Singapore for the first time in her career.
The world's top eight players will compete in the Oct. 21-28 round-robin tournament with a total prize purse of $7 million on the line.