Serena Williams was dethroned from world number one position as she was outplayed and beaten by Karolina Pliskova in the semifinals of the US Open.
Williams double-faulted on match point, losing 6-2 7-6 (7-5) to the 10th seed from Czech Republic.
The 34 year old American clearly looked tired and one will wonder if the lack of rest was a major factor as she clearly lacked the footwork.
But take nothing away from Karolina Pliskova, she took full advantage of the opportunity and was so aggressive especially with her first serve's which outworked Williams and her movement as as her timing.
With this result, Williams reign as world number one has ended.
She had also hoped to win an Open-era record 23rd major singles title.
She remains tied with Steffi Graf for both Grand Slam titles, and the WTA record of 186 successive weeks as world number one.
In the mean time,the woman who will succeed Serena Williams as World number one in the next WTA rankings, Angelique Kerber reached her third major final this year after dispatching Caroline Wozniacki in straight sets at the U.S. Open.
Kerber, who was already No. 1 before she even stepped on court as a result of Serena Williams' loss in the first semifinal, went out in a get new status, winning the first four games en route to a 6-4, 6-3 victory against Woznaicki, a former world number one now down at 74th in the rankings.
The German will face Pliskova on Saturday in a rematch of the final at Cincinnati nearly three weeks earlier.
Kerber would have taken over the No. 1 ranking then had she won that day, but Pliskova instead captured a breakthrough title and has ridden in that momentum since then and has gone on a ten game winning streak