Petra Kvitova upset defending champion Agnieszka Radwanska to reach the semi-finals of the Dubai Duty Free Tennis Championships on Thursday evening. The Czech has struggled since finishing 2011 on the brink of becoming world number one but last week she pushed Serena Williams hard in Doha and today she was far too strong for world number four Radwanska. Kvitova’s 6-2 6-4 victory was her first over a top-five player since 2011 and in the last four she will meet former world number one Caroline Wozniacki, who came from a set down to defeat Marion Bartoli. In a match full of service breaks, it was unorthodox Frenchwoman Bartoli who edged the first set but Wozniacki hit back to level and then withstood a Bartoli fightback from 2-5 down in the decider to win 4-6 6-1 6-4. The other semi-final will pit best friends and doubles partners Sara Errani and Roberta Vinci against each other. Vinci continued her giant-killing run, following up her victory over Angelique Kerber by dumping out seventh seed Sam Stosur 6-2 6-4 to reach the biggest singles semi-final of her career. Fellow Italian Errani, who beat Vinci in the quarter-finals of the US Open last year, failed to win a game in the second set against Russia’s Nadia Petrova but recovered to win 6-4 0-6 6-3.
