Pennetta knocks Wozniacki out of China Open

Italian Flavia Pennetta stunned world number one Caroline Wozniacki with a fierce 3-6, 6-0, 7-6 (7/2) comeback in the quarter-finals of the China Open on Friday.The Dane looked to be in control before Pennetta began a fightback, winning the second set to nil, and dominating a third set tie-break. Pennetta, the world number 26, had lost all five of their previous meetings.Wozniacki has claimed six WTA trophies this season but -- despite her world ranking -- is still searching for her first Grand Slam crown.Polands Agnieszka Radwanska, the 11th seed and a winner last week in Tokyo, reached the final four after Serbian Ana Ivanovic retired with a back injury while trailing 6-3, 3-2.Giant-killing Romanian qualifier Monica Niculescu fought back from a set down against former champion Maria Kirilenko to reach the semi-finals and keep her dream run alive.Niculescu, the world number 57, who knocked out French Open champion Li Na in the first round, recovered from a slow start to win 3-6, 6-3, 6-4.Niculescu will play the winner of the match between German ninth seed Andrea Petkovic and Russian 13th seed Anastasia Pavlyuchenkova.German ninth seed Andrea Petkovic completed the semi-final lineup with her defeat of Anastasia Pavlyuchenkova 6-3, 7-6 (7/2).In the mens draw, third seed Tomas Berdych crushed Fernando Verdasco 6-1, 6-0 in 65 minutes, one of the heaviest defeats of the Spaniards career.Berdych opened with a loss of serve but then turned on the afterburners to win 12 straight games.Berdych has yet to win a title in 2011. Only he and Frenchman Gael Monfils from the top 10 are without a trophy this year.He will play his seventh semi-final of the year against French top seed Jo-Wilfried Tsonga, who dispatched Spains Juan Carlos Ferrero 6-3, 6-4.Croatian Ivan Ljubicic beat Russian Mikhail Youzhny 7-6 (7/4), 6-7 (4/7), 6-2 and will Croatian Marin Cilic, a winner over South African Kevin Anderson 7-6 (7/4), 4-6, 6-1.