Roger Federer, of Switzerland, serves to Stanislas Wawrinka, of Switzerland, during their match at the BNP Paribas Open tennis tournament, Wednesday, March 13, 2013, in Indian Wells, Calif. (AP ... more 

Roger Federer, of Switzerland, serves to Stanislas Wawrinka, of Switzerland, during their match at the BNP Paribas Open tennis tournament, Wednesday, March 13, 2013, in Indian Wells, Calif. (AP Photo/Mark J. Terrill) less