Serena Williams reaches in WTA last four

Serena Williams reached the last four of the WTA Finals and was crowned year-end world number one without picking up a racquet on Friday when results went her way at the season finale in Singapore.

The four-time champion was in stark danger of crashing out but she earned a reprieve when Simona Halep, her tormentor in a crushing 6-0 6-2 defeat earlier this week, won a set against Ana Ivanovic.

And more stars aligned for the 18-time grand slam-winner when world number two Maria Sharapova made an early exit, ending her chances of overtaking the American in the year’s final rankings.

Caroline Wozniacki stormed past Petra Kvitova 6-2 6-3 to set up a semi-final against Williams on Saturday, while Halep will play Agnieszka Radwanska in the last four.

Ivanovic departs despite beating Halep 7-6 (9-7) 3-6 6-3, while Sharapova also leaves with her head held high after rallying for a 7-5 6-7 (4-7) 6-2 win over Radwanska.

Under complex round-robin calculations, Sharapova needed a straight-sets victory to survive and she came agonisingly close when she passed up three match points in the second set.

“I just really wanted to win this match. I had so many chances and it was just not the way that I wanted to go out in the tournament,” said the Russian.

“That was my goal no matter how physical the match or how tough it was to lose that second set was, I wanted to win it.”

While Sharapova’s season is over, Wozniacki’s is still very much in play after a victory over Kvitova that left her as the only player in the tournament to win all three group matches.

Super-fit Wozniacki, who is training for next month’s New York marathon in lieu of her cancelled wedding to golfer Rory McIlroy, again made all the running as she beat Kvitova in 69 minutes.

Following her three-hour slugfest against Sharapova and straight-sets win over Radwanska, the resurgent former world number one has hit a patch of form that has re-announced her as a force in women’s tennis.

“I believe in myself and I believe in my skills. I’ve been playing well, so I believed I could beat anyone,” said eighth-ranked Wozniacki, who described Friday’s win as one of her best.

“I obviously also knew that if I wasn’t playing up to my best I could lose to all of them. So I’m really pleased about the way this week has gone so far. I played really well. Today was a really great match for me.”

Later Ivanovic fought bitterly for the straight-sets win over Halep that she needed to stay alive, and momentum was with her when she came from behind to win the first set on a tie-breaker.

But the former French Open champion inexplicably missed an open-court volley as she was broken early in the second set, which she lost 6-3 to end her tournament hopes.

But like Sharapova, she gathered herself for an all-out effort in her final set of the season and she took it 6-3 to seal her 58th victory of the year, more than any other player.

Poland’s Radwanska needed Wozniacki to beat Kvitova to reach the semi-finals – a favour for which she promised to take her good friend shopping, on her credit card.

“Yeah, she told me that, too. I hope she’s going to keep her promise,” Wozniacki said. “She owes me a handbag. I think that’s what I’m going to go for.”

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