Australias Samantha Stosur clinched her head substantial slam by winning the U.S. launch happening September.STORY HIGHLIGHTSSamantha Stosur books her place concerning the semifinals by the WTA ChampionshipsStosur crushes Chinas Li Na 6-1 6-0 to charge encounter with Petra KvitovaVera Zvonareva to admit Victoria Azarenka concerning the other semi in imitation of Agnieszka Radwanskas defeatRadwanska fails concerning her try to cause somebody to endure four in imitation of a straight sets defeat by Kvitova U.S. unguarded champion Samantha Stosur stormed into the semifinals of the season-ending WTA Championships past crushing Chinas Li Na 6-1 6-0 inside Istanbul.