Serena stands alone

Serena Williams is hoping to join Steffi Graf and Margaret Court as five-time winners at the US Open. Timothy A. Clary/Getty Images

Serena Williams enters the semifinals as the United States’ lone chance at a singles champion at the 2013 US Open. American women have won 89 of the 126 singles titles awarded at the US Open. Those 89 titles have been won by 35 different women. The other women’s semifinalists – Li Na of China, Victoria Azarenka of Belarus and Flavia Pennetta of Italy – are hoping to claim the first US Open women’s singles title in the history of their countries. Other than the United States, only three countries have won more women's singles titles than Serena -- Australia with six and Belgium and Germany with five. The men's semifinalists represent Serbia (Novak Djokovic), Spain (Rafael Nadal), France (Richard Gasquet) and Switzerland (Stanislas Wawrinka).