Azarenka first reached the top of the rankings after winning the Australian Open this year. She dropped behind Maria Sharapova after Sharapova took the French Open crown. Azarenka went back to No. 1 after Wimbledon, where Serena Williams grabbed the first half of a Wimbledon-Olympic gold medal double.
For Azarenka to get to the finals in New York she'll, if the draw plays out, face either three-time Open winner Kim Clijsters or defending champion Samantha Stosur in the quarterfinals. If she gets beyond that, Sharapova, the 2006 Open winner, could be waiting in the semifinals.
Williams, coming off the titles at the Wimbledon Championship and the Olympics and who won the U.S. Open in 1999, 2002 and 2008, is in the same half of the draw as world No. 2 Agnieszka Radwanska. Williams could go against eighth-seeded Caroline Wozniacki. Radwanska has sixth-seeded Angelique Kerber in her quarter.
There will not be an all-Williams final, but Serena could player sister Venus in the semifinals.
The women's single U.S. Open final is scheduled for Sept. 8. The tournament begins Monday.