US Open Breakfast - Serena dethroned, new world number one Kerber to meet Pliskova in final

For the second-straight year, Serena Williams was upset in the US Open semi-finals, this time courtesy a dispiriting 6-2 7-6 (7-5) loss to Czech 10th seed Karolina Pliskova. A year ago Williams arrived in the final four on the cusp of a rare calendar-year Grand Slam when unseeded Italian Roberta Vinci, a 300-to-1 longshot, recorded one of the biggest upsets in major tennis.

History continued to beckon Williams, who would have stood alone as greatest Grand Slam champion in the professional era if she had claimed a 23rd title and moved past Steffi Graf.

Williams, who had to reach the final to have any chance of retaining top spot, relinquished the ranking to Germany's Angelique Kerber. Serena had been in the top spot for the last 186 weeks, a run which tied Graf for the longest streak in history.

Pliskova, who became the first Czech woman to make the US Open final since Helena Suková in 1993, played a flawless first set, helped by her thumping first serve. She relinquished a break advantage midway in the second but prevailed in a tense tiebreak.

"I don't believe it. Actually, I do believe it," Pliskova said in a courtside interview after the game. "I always knew I have a chance to beat anybody if I'm playing my game.

"But this is something amazing.

"Serena, she's a champion so it's never easy to play her. You saw even when she was down a break she's still fighting so it's very hard."

After the match Williams revealed she had been playing through a "serious" knee injury at the US Open.

Germany's new World No.1 Kerber will be waiting for the Czech in the final.

Kerber nudged Serena from the summit after overcoming former No. 1 Caroline Wozniacki in comfortable fashion.

In an intriguing semi-final clash between the Dane - who has never won a Grand Slam title - and Kerber, who claimed a first major at the Australian Open in January, it was the German who took command.

The lefty reached her third major final this year and will next 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.

"It's incredible to be in the final and to be the world number one, it's a great day," said Kerber who has made the final without dropping a set.

Kerber becomes only the second German woman to achieve this historic milestone of becoming world No.1 since computer rankings were introduced in 1975, and the first since Steffi Graf spent the last of her record 377 weeks at No.1 in March 1997. She is also the oldest player to make her debut at No.1, a record previously held by Jennifer Capriati, who was 25 years, 200 days when she reached No.1 in October 2001.

Japanese trailblazer Kei Nishikori will still be on cloud nine after ending Andy Murray's magical summer in the quarter-finals on Wednesday. The 26-year-old, a US Open runner-up two years ago, is one of the fittest players on tour, and will need to be at his very best once again in order to repel third seed Stan Wawrinka, who is into his third semi-final in New York. You can read the full preview for Day 12, including TV times here.