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

2011 U.S. Open: Federer Is Set to Battle Djokovic in Semifinals - The New York Times

Roger Federer beats Novak Djokovic in Dubai Championship semi-finals - ABC News

Murray to face Djokovic after five-set defeat of Federer

Roger Federer vs. Novak Djokovic: A Rivalry That Sizzles in the Paris Sun, News, Scores, Highlights, Stats, and Rumors

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

Roger Federer: You can't always win, spc talk

Flawless Roger Federer reaches quarter finals of US Open, The Independent

U. S. Open 2011 The CouchExpert

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

Australian Open 2012: Federer vs Nadal, What Each Star Must Do to Win, News, Scores, Highlights, Stats, and Rumors

Novak Djokovic Joins Roger Federer in an Astonishing Record That Even Rafael Nadal, Rod Laver or Andre Agassi Couldn't Achieve Despite Career Grand Slams - The SportsRush

Djokovic–Federer rivalry - Wikipedia

Rafael Nadal withdraws from U.S. Open with ongoing knee injury - Sports Illustrated

Generation game: The kids threatening Roger Federer, Novak Djokovic, Andy Murray and Rafael Nadal at the top of tennis, The Independent

If Djokovic defeated Federer (and Nadal) at the 2011 French Open, could he have defeated Nadal in upcoming seasons there? - Quora