World number four Petra Kvitova has crashed out of the US Open. In the third round, the third seeded Czech was stunned by unseeded Aleksandra Krunic of Serbia, in straight sets, 4-6, 4-6. World number two Simona Halep, Agnieszka Radwanska and Angelique Kerber are the big names who have made a shock exit from this fourth and final Grand Slam of the season.However, top seeds Novak Djokovic and Serena Williams, Stanislas Wawrinka, Andy Murray, Eugenie Bouchard and Victoria Azarenka progressed to the pre-quarterfinals.Sania Mirza booked a quarterfinal berth in the Mixed Doubles and the pre-quarterfinal slot in the Women's Doubles section. Leander Paes also made it to the Mixed Doubles quarterfinals with his Zimbabwean team-mate Cara Black. While Sania is the top seed in the Mixed Doubles with Brazilian Bruno Soares, she and Cara Black are placed third in the Women's Doubles.