Novak Djokovic of Serbia returns the ball during the men's singles 3rd round match against Joao Sousa of Portugal at the 2013 U.S. Open tennis championships in New York, the United States, on Sept. 1, 2013. Novak Djokovic won 3-0 to enter the next round. (Xinhua/Wang Lei)
This multi-exposure picture shows Novak Djokovic of Serbia returning the ball during the men's singles 3rd round match against Joao Sousa of Portugal at the 2013 U.S. Open tennis championships in New York, the United States, on Sept. 1, 2013. Novak Djokovic won 3-0 to enter the next round. (Xinhua/Wang Lei)
Novak Djokovic of Serbia returns the ball during the men's singles 3rd round match against Joao Sousa of Portugal at the 2013 U.S. Open tennis championships in New York, the United States, on Sept. 1, 2013. Novak Djokovic won 3-0 to enter the next round. (Xinhua/Wang Lei)
Novak Djokovic of Serbia returns the ball during the men's singles 3rd round match against Joao Sousa of Portugal at the 2013 U.S. Open tennis championships in New York, the United States, on Sept. 1, 2013. Novak Djokovic won 3-0 to enter the next round. (Xinhua/Wang Lei)
Novak Djokovic of Serbia returns the ball during the men's singles 3rd round match against Joao Sousa of Portugal at the 2013 U.S. Open tennis championships in New York, the United States, on Sept. 1, 2013. Novak Djokovic won 3-0 to enter the next round. (Xinhua/Wang Lei)
Novak Djokovic of Serbia returns the ball during the men's singles 3rd round match against Joao Sousa of Portugal at the 2013 U.S. Open tennis championships in New York, the United States, on Sept. 1, 2013. Novak Djokovic won 3-0 to enter the next round. (Xinhua/Wang Lei)
Novak Djokovic of Serbia returns the ball during the men's singles 3rd round match against Joao Sousa of Portugal at the 2013 U.S. Open tennis championships in New York, the United States, on Sept. 1, 2013. Novak Djokovic won 3-0 to enter the next round. (Xinhua/Wang Lei)
