Images from Tuesday's action at the U.S. Open
Victoria Azarenka, of Belarus, returns a shot to Ana Ivanovic, of Serbia, during the quarterfinals of the 2013 U.S. Open tennis tournament, Tuesday, Sept. 3, 2013, in New York.Julio Cortez/The Associated Press
Ana Ivanovic of Serbia hits a smash to Victoria Azarenka of Belarus at the U.S. Open tennis championships in New York September 3, 2013.RAY STUBBLEBINE/Reuters
Victoria Azarenka of Belarus hits a return to Ana Ivanovic of Serbia at the U.S. Open tennis championships in New York September 3, 2013.EDUARDO MUNOZ/Reuters
Victoria Azarenka of Belarus argues a call during her match against Ana Ivanovic of Serbia at the U.S. Open tennis championships in New York September 3, 2013. The 2012 runner-up at Flushing Meadows won 4-6, 6-3, 6-4.ADAM HUNGER/Reuters
Mikhail Youzhny of Russia hits a return to Lleyton Hewitt of Australia at the U.S. Open tennis championships in New York September 3, 2013.ADAM HUNGER/Reuters
Lleyton Hewitt, of Australia, returns a shot to Mikhail Youzhny, of Russia, during the fourth round of the 2013 U.S. Open tennis tournament, Tuesday, Sept. 3, 2013, in New York.Kathy Willens/The Associated Press
Ekaterina Makarova of Russia hits a return to Li Na of China at the U.S. Open tennis championships in New York September 3, 2013.RAY STUBBLEBINE/Reuters
Li Na of China hits a return to Ekaterina Makarova of Russia at the U.S. Open tennis championships in New York September 3, 2013.EDUARDO MUNOZ/Reuters
Li Na of China celebrates after defeating Ekaterina Makarova of Russia 6-4 6-7(5) 6-2 at the U.S. Open tennis championships in New York September 3, 2013.EDUARDO MUNOZ/Reuters
Lleyton Hewitt of Australia check on an elbow injury during his match against Mikhail Youzhny of Russia at the U.S. Open tennis championships in New York September 3, 2013.ADAM HUNGER/Reuters
Mikhail Youzhny, of Russia, salutes the crowd after beating Lleyton Hewitt, of Australia 6-3 3-6 6-7(3) 6-4 7-5, during the fourth round of the 2013 U.S. Open tennis tournament, Tuesday, Sept. 3, 2013, in New York.KATHY WILLENS/The Associated Press
Mikhail Youzhny of Russia signs autographs for fans following his victory over Lleyton Hewitt of Australia at the U.S. Open tennis championships in New York September 3, 2013.ADAM HUNGER/Reuters
Novak Djokovic of Serbia serves to Marcel Granollers of Spain at the U.S. Open tennis championships in New York September 3, 2013.RAY STUBBLEBINE/Reuters
Novak Djokovic of Serbia (R) is congratulated by Marcel Granollers of Spain after Djokovic won their match 6-3, 6-0, 6-0 at the U.S. Open tennis championships in New York September 3, 2013.MIKE SEGAR/Reuters
Serena Williams, of the United States, watches a return to Carla Suarez Navarro, of Spain, during a quarter-final of the U.S. Open tennis tournament, Tuesday, Sept. 3, 2013, in New York.CHARLES KRUPA/The Associated Press
Denis Istomin, of Uzbekistan, tosses the ball on a serve to Andy Murray, of Britain, during the fourth round of the U.S. Open tennis tournament, Tuesday, Sept. 3, 2013, in New York.CHARLES KRUPA/The Associated Press
Andy Murray, of Britain, follows through on a serve to Denis Istomin, of Uzbekistan, at the U.S. Open tennis tournament, Tuesday, Sept. 3, 2013, in New York.CHARLES KRUPA/The Associated Press
Serena Williams, of the United States, bounces the ball before a serve to Carla Suarez Navarro, of Spain, during a women's quarter-final of the U.S. Open tennis tournament, Tuesday, Sept. 3, 2013, in New York. Williams advanced with a 6-0, 6-0 victory.CHARLES KRUPA/The Associated Press
Stanislas Wawrinka of Switzerland slips and falls during his match against Tomas Berdych of the Czech Republic at the U.S. Open tennis championships in New York September 3, 2013. Wawrinka overcame the fall to win 3-6 6-1 7-6(6) 6-2.MIKE SEGAR/Reuters
Andy Murray, of Britain, serves to Denis Istomin, of Uzbekistan, during the fourth round of the U.S. Open tennis tournament, Tuesday, Sept. 3, 2013, in New York. Murray advanced with a 6-7(5) 6-1 6-4 6-4 victory.CHARLES KRUPA/The Associated Press