Andy Murray, Milos Raonic among those in action
The Flushing Meadows Park Unisphere is seen from the grounds of the U.S. Open tennis tournament in New York, August 25, 2014.MIKE SEGAR/Reuters
A vendor sells programs before matches begin at the 2014 U.S. Open tennis tournament in New York, August 25, 2014.MIKE SEGAR/Reuters
Simona Halep, of Romania, returns a serve against Danielle Rose Collins, of the United States, during the opening round of the 2014 U.S. Open tennis tournament, Monday, Aug. 25, 2014, in New York.Elise Amendola/The Associated Press
Agnieszka Radwanska of Poland hits a return to Sharon Fichman of Canada during their match at the 2014 U.S. Open tennis tournament in New York, August 25, 2014.ADAM HUNGER/Reuters
Angelique Kerber, of Germany, returns a shot against Ksenia Pervak, of Russia, during the opening round of the 2014 U.S. Open tennis tournament, Monday, Aug. 25, 2014, in New York.Matt Rourke/The Associated Press
Angelique Kerber of Germany hits a return to Ksenia Pervak of Russia during their match at the 2014 U.S. Open tennis tournament in New York, August 25, 2014.EDUARDO MUNOZ/Reuters
Supporters of Andy Murray of Britain cheer before his match against Robin Haase of the Netherlands at the 2014 U.S. Open tennis tournament in New York, August 25, 2014.ADAM HUNGER/Reuters
Andy Murray of Britain hits a return to Robin Haase of the Netherlands during their match at the 2014 U.S. Open tennis tournament in New York, August 25, 2014.ADAM HUNGER/Reuters
Andrea Petkovic, of Germany, returns a shot against Ons Jabeur, of Tunisia, during the opening round of the 2014 U.S. Open tennis tournament, Monday, Aug. 25, 2014, in New York.Frank Franklin II/The Associated Press
Ons Jabeur, of Tunisia, returns a shot against Andrea Petkovic, of Germany, during the opening round of the 2014 U.S. Open tennis tournament, Monday, Aug. 25, 2014, in New York.Frank Franklin II/The Associated Press
Lucie Safarova, of the Czech Republic, returns a shot against Timea Babos, of Hungary, during the opening round of the 2014 U.S. Open tennis tournament, Monday, Aug. 25, 2014, in New York.Frank Franklin II/The Associated Press
A fan watches Simona Halep of Romania play Danielle Rose Collins of the U.S. at the 2014 U.S. Open tennis tournament in New York, August 25, 2014.MIKE SEGAR/Reuters
Benoit Paire, of France, flips his racket after a shot against Julien Benneteau, of France, during the opening round of the 2014 U.S. Open tennis tournament, Monday, Aug. 25, 2014, in New York.Frank Franklin II/The Associated Press
Jo-Wilfried Tsonga of France serves to Juan Monaco of Argentina during their match at the 2014 U.S. Open tennis tournament in New York, August 25, 2014.EDUARDO MUNOZ/Reuters
Juan Monaco of Argentina hits a return to Jo-Wilfried Tsonga of France during their match at the 2014 U.S. Open tennis tournament in New York, August 25, 2014.EDUARDO MUNOZ/Reuters
Venus Williams, of the United States, serves against Kimiko Date-Krumm, of Japan, during the opening round of the 2014 U.S. Open tennis tournament, Monday, Aug. 25, 2014, in New York.Elise Amendola/The Associated Press
Aleksandra Wozniak, of Canada, returns shot against Kurumi Nara, of Japan, during the opening round of the 2014 U.S. Open tennis tournament, Monday, Aug. 25, 2014, in New York.Frank Franklin II/The Associated Press
Ball persons attempt to swat away a bee from Kimiko Date-Krumm, of Japan, during the opening round of the 2014 U.S. Open tennis tournament against Venus Williams, of the United States, Monday, Aug. 25, 2014, in New York.Elise Amendola/The Associated Press
Venus Williams ducks a bee on Ashe Stadium court at the 2014 U.S. Open tennis tournament at USTA Billie Jean King National Tennis Center.Robert Deutsch
Daniela Hantuchova, of Slovakia, returns a shot against Romina Oprandi, of Swizterland, during the opening round of the 2014 U.S. Open tennis tournament, Monday, Aug. 25, 2014, in New York.Frank Franklin II/The Associated Press