Previous Novak Djokovic, of Serbia, returns the ball against Stanislas Wawrinka during a match at the BNP Paribas Open tennis tournament in Indian Wells. © 2009 AP Photo/Mark Avery Next

Novak Djokovic, of Serbia, returns the ball against Stanislas Wawrinka during a match at the BNP Paribas Open tennis tournament in Indian Wells. © 2009 AP Photo/Mark Avery