Australia\'s Sam Stosur and Italy\'s Sara Errani are to clash in the French Open semifinals after both won Tuesday\'s quarterfinals in straight sets. Sixth-seeded Stosur, a Roland Garros finalist in 2010, swept aside Dominika Cibulkova with surprising ease 6-4, 6-1. The Slovakian Cibulkova, seeded 15, had dumped world No. 1 Victoria Azarenka out of the tournament in the previous round, and was mooted as a dark horse for the title. Errani, meanwhile, ousted a higher seed for the second time in the draw, downing Germany\'s 10th seed Angelique Kerber 6-3, 7-6 (2). She had earlier taken care of Serbia\'s Ana Ivanovic, the 13th seed, in the third round. The other quarterfinals pit Wimbledon champion Petrova Kvitova against Kazakhstan\'s Yaroslava Shvedova, who slayed reigning champion Li Na in the fourth round; and Estonia\'s Kaia Kanepi against Maria Sharapova, the second seed.