Switzerland's Roger Federer returns the ball to his compatriot Stanislas Wawrinka during "The match for Africa 2" charity tennis match in Zurich December 21, 2014. REUTERS/Arnd Wiegmann (SWITZERLAND ... more 
Switzerland's Roger Federer returns the ball to his compatriot Stanislas Wawrinka during "The match for Africa 2" charity tennis match in Zurich December 21, 2014. REUTERS/Arnd Wiegmann (SWITZERLAND - Tags: SPORT TENNIS) less 
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Reuters | Photo By ARND WIEGMANN / REUTERS
Sun, Dec 21, 2014 3:59 PM EST