MELBOURNE, Australia —Jan 28, 2019— Australian Open champion Naomi Osaka is the youngest woman to make her debut at No. 1 in nine years and the first man or woman from Asia to lead the tennis rankings.
Simona Halep’s 48-week stay atop the WTA ended Monday. She slid to No. 3 after a fourth-round loss to Serena Williams.
Williams missed the tournament last year after having a baby; her run to the quarterfinals this time pushed her up five places to No.