Defending champion Kim Clijsters reached the semi-finals of the Australian Open after beating Caroline Wozniacki in straight sets on Tuesday, ending the Dane's stay at world number one.
Clijsters held off a determined fight-back from the 21-year-old top seed to win 6-3, 7-6 (7-4) in just under two hours and set up a semi-final date against Victoria Azarenka.
By failing to reach the semi-finals, Wozniacki is guaranteed to lose her number one ranking to either Azarenka, Petra Kvitova or Maria Sharapova when the new standings are released next Monday.
And the top seed will face inevitable questions over how she managed to hold onto the number one spot for 67 of the past 68 weeks without winning a grand slam.
Wozniacki played her usual counter-punching game on Tuesday with plenty of retrieving from the baseline, but she did not have a weapon to damage Clijsters.
The Belgian played much better than in her fourth round win over China's Li Na, and showed no ill-effects from the ankle injury she suffered during that match.
Clijsters broke Wozniacki four times in the first set as she dominated her younger rival on both her forehand and backhand sides.
And although Wozniacki broke twice herself, she was always playing catch-up and never looked like taking the set.
The second set followed a similar pattern, but Clijsters faltered while serving for the match at 5-3.
The tie-break went with serve until 4-4, when Clijsters stepped up to win the next three points and seal victory with a simple put-away into the open court.
"It didn't feel like being up a set and 5-2," the Belgian said.
"I really had to work at it. Caroline changed her tactics (in the second set) and became a bit more aggressive."
In the new rankings to be published next Monday, French Open champion Li Na, who fell to Clijsters in the fourth round, will slip to ninth in the world, WTA projections show.
China's Li will lose the points she earned for finishing as runner-up to Belgium's Clijsters in 2011, resulting in a drop of three places from number six.
US Open champion Samantha Stosur's first-round loss has not done her significant harm, with the Australian set to stay at number five.
And former world number one Ana Ivanovic of Serbia, who lost in the fourth round to Czech second seed Kvitova, is projected to return to the top 20. She is currently ranked number 22.
Despite her long reign at the top, Wozniacki has failed to win a grand slam, with critics saying she could not be considered the best player in the world until she takes one of the sport's major prizes.
Tennis great Martina Navratilova weighed into the debate on Monday, saying the women's game was crying out for a new star and the rankings were weighted too much towards quantity of matches, rather than quality of opposition.
"Clearly nobody feels that Wozniacki is a true number one," she said.
"If we still had the same ranking system we were using six years ago when they were giving bonus points for beating players, Kvitova would have ended up number one because she had beaten more top players than Wozniacki."
Azarenka also reached the semi-finals on Tuesday after beating Agnieszka Radwanska, while Sharapova and Kvitova play their last-four matches on Wednesday.
AFPTags: sport, australian-open, tennis, melbourne-3000, vic, australia First posted January 24, 2012 16:33:46