Supporters wearing face masks of Roger Federer cheer on during an ATP World Tour Finals singles tennis match between Roger Federer of Switzerland and Janko Tipsarevic of Serbia at the O2 Arena in ... more 
Supporters wearing face masks of Roger Federer cheer on during an ATP World Tour Finals singles tennis match between Roger Federer of Switzerland and Janko Tipsarevic of Serbia at the O2 Arena in London, Tuesday, Nov. 6, 2012. (AP Photo/Sang Tan) less 
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Associated Press | Photo By Sang Tan
Tue, Nov 6, 2012 1:21 PM EST