Roger Federer of Switzerland celebrates at match point after beating Rafael Nadal 

Roger Federer of Switzerland celebrates at match point after beating Rafael Nadal of Spain during their round robin singles tennis match at the ATP World Tour Finals at O2 Arena in London, Tuesday, Nov. 22, 2011.  (AP Photo/Kirsty Wigglesworth)
Associated Press
Roger Federer of Switzerland celebrates at match point after beating Rafael Nadal of Spain during their round robin singles tennis match at the ATP World Tour Finals at O2 Arena in London, Tuesday, Nov. 22, 2011. (AP Photo/Kirsty Wigglesworth)
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