Oldest female tennis player to debut at No.1 in the world rankings

Germany's Angelique Kerber (b. 18 January 1988) ended Serena Williams' record-equalling 186 successive weeks at the top of the Women's Tennis Association (WTA) world rankings to become the oldest female player to claim the No.1 spot for the first time, aged 28 years 238 days as of 12 September 2016. Kerber won the Australian Open – her maiden Grand Slam title – and the US Open in 2016 and reached singles finals at Wimbledon, the Olympic Games and the season-ending WTA Finals in Singapore.

Kerber's rise to the top was confirmed when Williams was defeated 6–2, 7–6 by Karolina Pliskova in the semi-finals of the US Open on 9 September 2016. The next day, No.2 seed Kerber beat 10th seed Pliskova in the final, 6–3, 4–6, 6–4.

Kerber is only the second German woman to top the world rankings since they were introduced in 1975, after Steffi Graf (a record 377 weeks at No.1 until March 1997).

Jennifer Capriati (USA, b. 29 March 1976) was previously the oldest woman to debut at No.1, aged 25 years 200 days in October 2001.

Williams had held the No.1 spot since 18 February 2013. The American's sixth stint at the top since first becoming world No.1 on 8 July 2002 tied Steffi Graf for the most consecutive weeks in pole position – 186. Williams had a total of 309 weeks at the top of the world rankings, as of 31 October 2016.

Kerber defeated Williams 6–4, 3–6, 6–4 in the Australian Open final on 30 January 2016. She lost to Williams (7–5, 6–3) in the Wimbledon final, in the singles final at Rio 2016 she was defeated 6–4, 6–1 by Monica Puig, and at the WTA Finals in Singapore on 30 October 2016, she went down 6–3, 6–4 to Dominika Cibulková.