Novak Djokovic of Serbia returns the ball to Ivan Ljubicic of Croatia during the first round of the U.S. Open tennis tournament in New York...

NEW YORK - SEPTEMBER 01: Novak Djokovic of Serbia returns a shot against Ivan Ljubicic of Croatia during day two of the 2009 U.S. Open at the USTA Billie Jean...

Spanish Rafael Nadal hits a return to his croatian opponent Ivan Ljubicic during their Monte Carlo ATP Masters Series tournament tennis match on April 17, 2009 in Monaco...

Spainish Rafael Nadal hits a return to his Croatian opponent Ivan Ljubicic during their Monte Carlo ATP Masters Series tournament tennis match on April 17, 2009 in Monaco...

Andy Murray of Great Britain hits a return against Ivan Ljubicic of Croatia during the quarterfinals at the Indian Wells ATP tennis tournament in Indian Wells, California...

Ivan Ljubicic of Croatia plays a return stroke during his men's singles match against Jo-Wilfried Tsonga...

Marcos Baghdatis from Cyprus returns a backhand during his game against Ivan Ljubicic from Croatia during the Kooyong Classic tennis tournament in Melbourne, Thursday, Jan. 15, 2009. Baghdatis won...

Jo-Wilfried Tsonga of France plays a return stroke during his men's singles match against Ivan Ljubicic of Croatia at the Australian Open tennis tournament in Melbourne on January 22, 2009. The match...