Naomi Osaka (大坂 なおみ Ōsaka Naomi, born October 16, 1997) is a professional tennis player who represents Japan. She is the current US Open and Australian Open champion in women's singles, and No. 1 in the Women's Tennis Association (WTA) rankings, which she achieved in January 2019.
Born in Japan to a Haitian father and a Japanese mother, Osaka has lived in the United States since she was three years old. She came to prominence at the age of sixteen 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 Japan to enter the top 50 of the WTA rankings. Osaka made her breakthrough into the upper echelon of women's tennis in 2018, when she won her first WTA title at the Indian Wells Open. In September, she won the US Open, defeating 23-time major champion Serena Williams in the final to become the first Japanese player to win a Grand Slam singles tournament. Her second Grand Slam title came in January 2019, when she won the Australian Open, becoming the first Asian player to be the world's number one.
Osaka is known for her aggressive playing style with a powerful serve. Off the court, she is known for her shy, candid personality and her occasional spontaneous humour.