US Open 2011: Roger Federer struggles to accept Novak Djokovic defeat, US Open 2011

Roger Federer was left stung by Novak Djokovic's comeback in their five-set US Open semi-final

Federer confident of return to top spot, Sports

Novak Djokovic stuns Roger Federer in US Open semi-final, Roger Federer

AUSTRALIAN OPEN 2011: Roger Federer surrenders two-set lead before edging past Gilles Simon

To Lose Against Someone Like That Is Disappointing: When Roger Federer Was Infuriated by Novak Djokovic at US Open - The SportsRush

French Open 2011: Rafael Nadal Beats Roger Federer In Roland Garros Yet Again - SB Nation Bay Area

Dubai Open 2011: Novak Djokovic inflicts more misery on Roger Federer

Why Hasn't Roger Federer Been Successful at the US Open Since 2008? - EssentiallySports

Wimbledon: Novak Djokovic and Roger Federer reach men's final

Novak Djokovic defeats Roger Federer in Italian Open final - Los Angeles Times

2011: Djokovic hits return heard 'round the world to beat Federer