Samantha Stosur (born March 30, 1984) is an Australian professional women's tennis player and grand slam singles, doubles and mixed doubles champion. In 2006, toser and American partner lisa ramon reached the top of the women's tennis federation (WTA) doubles rankings. 2011 she won her first grand slam singles title with a 2-0 victory over serena Williams in the women's final at the U.S. open. The 2011 WTA year-end ranking is no. 6. Zhang shuai and stosur won the 2019 Australian open women's doubles final 6-3/6-4, defeating defending champion babs and kristina meladovich to clinch their first grand slam title together.