Novak Djokovic came hurtling into the Barclays ATP World Tour Finals on a terrific tear. But there was a little hiccup at the O2 Arena on the way to the Sunday championship final -- a loss to a guy named Federer.
And now, after Saturday's masterful 6-3, 6-3 victory over Rafael Nadal, Djokovic has a chance to punctuate one of the great years in tennis history with his fourth consecutive year-end championship.
And just to ramp up the degree of difficulty, he'll have to do it against a bearded Roger Federer (on ESPN2 & WatchESPN, Sunday, 1 p.