Naomi Osaka is a Japanese professional tennis player. She was ranked as the world No. 1 in women's singles by the WTA for 25 weeks starting in January 2019, the first Asian player to hold the top ranking in singles. Osaka has won seven career singles titles, including four majors: two each at the Australian Open and the US Open. She is the first Japanese player to win a major singles title.
Born in Japan to a Haitian-American father and a Japanese mother, Osaka has lived and trained in the United States since age three. She came to prominence at age 16 when she defeated former US Open champion Samantha Stosur in her WTA Tour debut at the 2014 Stanford Classic. Two years later, she reached her first WTA final at the 2016 Pan Pacific Open in Tokyo and entered the top 50 of the WTA rankings. Osaka broke into the upper echelon of women's tennis in 2018, winning her first Tour title at the Indian Wells Open, then defeating Serena Williams in the final of the US Open. After winning the Australian Open in early 2019, she reached the world No. 1 ranking for the first time.