Novak Djokovic of Serbia holds up his trophy after the final of the China Open tennis tournament at the National Tennis Stadium in Beijing, China Sunday, Oct. 6, 2013. Djokovic defeated Rafael Nadal of Spain 6-3, 6-4. (AP Photo)
Italy's Fabio Fognini celebrates with the trophy after he won the final match of the bet-at-home ATP tennis tournament against Argentina's Frederico Delbonis in Hamburg, Germany Sunday July 21, 2013. (AP)
Dominika Cibulkova holds up the winner's trophy after defeating Agnieszka Radwanska 3-6, 6-4, 6-4 in the finals of the Bank of the West Classic tennis tournament on Sunday, July 28, 2013, in Stanford, Calif.
Milos Raonic of Canada, left, holds his trophy next to runner-up Tomas Berdych of the Czech Republic at the final of the Thailand Open tennis tournament in Bangkok, Thailand, Sunday, Sept. 29, 2013. Raonic won 7-6, 6-3. (AP)
Frances tennis player Richard Gasquet leaves the draw ceremony for the upcoming Davis Cup tennis tournament between Argentina and France in Buenos Aires, Argentina, Thursday, April 4, 2013. Gasquet was replaced by Gilles Simon. Argentina will face France in the Davis Cup World Group quarterfinals April 5-7. (AP Photo/Victor R. Caivano) Next
Marin Cilic, of Croatia, holds up the championship trophy after defeating Kei Nishikori, of Japan, in the championship match of the 2014 U.S. Open tennis tournament, Monday, Sept. 8, 2014, in New York. (AP)
Tommy Haas of Germany poses with the trophy after winning the final match against Robin Haase of the Netherlands at the Erste Bank Open tennis tournament in Vienna, Austria, Sunday, Oct. 20, 2013. (AP)