MADRID –  The early session in the Mutua Madrid Open tennis tournament saw one major surprise as number four seed Jo-Wilfred Tsonga was knocked out of the tournament by number 16 seed Alexandr Dolgopolov.Dolgopolov overcame Tsonga 7-5, 3-6, 7-6(2) in two hours and 18 minutes to qualify for the quarter-finals. Number six seed Tomas Berdych continued his progress into the last eight with a comfortable 6-1, 6-1 victory over Gael Monfils in a match that lasted just 50 minutes.In the women’s competition, Serena Williams continued her progress into the last eight. Williams, who is seeded nine in Madrid, overcame the loss of the first set against number six seed, Caroline Wozniacki to win the last two set of her match 6-3, 6-2 to book a Quarter-final meeting with Maria Sharapova, who had a walkover in her game after her rival Lucie Safarova was forced to pull out with a gastro-intestinal illness.Speaking to the press after her win, Williams was relaxed and joked about the slippery conditions on the controversial blue clay court. "I felt a bit like an ice-skater out there, but I can ice skate, so that’s OK,” she said, before admitted she would be the underdog against Sharapova. Qualifier Lucie Hradecka is the surprise of the tournament and she progressed to a last eight meeting against Samantha Stosur thanks to a 6-2, 7-5(5) victory over Ekaterina Makarova. Finally number four seed Agnieszka Radwanska is also into the last eight after a narrow, 7-6(1), 6-4 triumph against Italian, Roberta Vinci.