Nadal reclaims top ranking after Berdych retires in China Open

Rafa Nadal will return to the top of the world rankings after Tomas Berdych retired with a back injury during their China Open semi-final on Saturday.

Serb Novak Djokovic, who will lose top spot when the new rankings are announced on Monday, brushed aside Frenchman Richard Gasquet 6-4 6-2 in the other semi-final to set up a mouth-watering final against arch-rival Nadal.

Berdych, trailing 2-4 in the opening set, tweaked his back while running for a backhand slice and needed a medical time- out.

He did return to the court but after a few points decided he could no longer continue, handing the 27-year-old Spaniard an easy passage to Sunday's final.

Nadal, who boosted his Grand Slam singles tally to 13 this year by winning the French and US Opens, has not been ranked number one since July 2011 but has produced a stunning run since returning from a long injury layoff in February.

"(This is) a great year, one of the best years of my career without any doubt," Nadal told reporters.

"(It) sure is special be back to the top position of the rankings after more than a half year without playing tennis.

"At the end, it's just a number... What (makes) me happy is (everything) I did to be back where I am today."

He has lost two finals since his return, winning 10 tournaments and adding over $10 million in prize money in 2013.

The semi-final victory extended Nadal's winning run to 21 matches and another triumph on Sunday would give him his first China Open title since 2005.

"(It) will be a great finish (to) the season if I am able to finish the season (at) the No. 1 spot," the Spaniard added. "For that, I am sure I need to win more matches if I want to be there.

"I (won't) go to sleep tonight feeling that I am the best player of the world. That's something that I never thought, and I don't... think (that) now today.

"I played a very complete season, and that's why I am the best in the rankings today."

His job will not be easy, though, as Djokovic might have a point to prove.

The Serb was broken by Gasquet in the fourth game of the opening set but came back strongly to advance.

Serena eyes 10th title of the season

World number one Serena Williams and Serbian eighth seed Jelena Jankovic set up a final showdown in the China Open after their contrasting victories in the semi-finals on Saturday.

The top-seeded American, who has now won 72 matches in 2013 and a prize purse of more than $9 million, hit 31 winners to thrash Poland's Agnieszka Radwanska 6-2 6-2.

But former world number one Jankovic had to rally from a set down to notch up her first career win against ninth seed Petra Kvitova 6-7(7) 6-1 6-1.

The 32-year-old Williams, who will be eyeing her 10th title of the season on Sunday, received medical attention on her back during the second set but it provided no respite for Radwanska.

"Playing against Agnieszka, she plays like magic, she can move the ball left and right - she can do anything with her shots," Williams told reporters.

"So for me today it was just important to try to stay ahead of her, or one step ahead of her. I just tried to do that today and I'm happy with how things went."

Kvitova, who won her second WTA title of the year last week in Tokyo, edged Jankovic in the tiebreak to bag the first set but a flurry of errors in the second set handed the momentum back to the Serb.

"I lost to her the last two times we played. She has always given me a lot of trouble and didn't allow me to play my game," Jankovic told reporters. "Even today in the first set she was controlling the points.

"I was still there, but didn't feel comfortable. But in the next two sets I felt like I went on top of her and took control. Then as the match went on I think she got a little bit tired... and then I had everything in my hands, pretty much."

The Serb, who reached the top of women's world rankings in 2008, had no qualms in admitting that she had to be at her best to even have a chance against Williams, whom she has beaten four out of 10 times in the past.

"She's in unbelievable form. Even though I have beaten her in the past... I think she's the most difficult player to play against," Jankovic said.

"She has a lot of experience, winning a lot of titles and winning pretty much everything there is to win.

"She's physically so strong, I think stronger than 99 percent of the players. She has all the shots. When she's on top of her game, it's very difficult to beat her."