Novak Djokovic shrugged off a back scare to defeat defending champion Rafael Nadal 6-4, 6-2, 6-7(3), 6-1 to clinch the US Open on Monday, his third Grand Slam title of the year in an epic, brutal final.The World No.1 Serb, who had already won the Australian Open before defeating Nadal at Wimbledon, racked up his 64th win against just two losses all year.But having been just two points from the title in the 12th game of the third set, his dreams were almost shattered when he dropped the set on a tiebreaker and needed a medical time-out on a strained back muscle.Victory represented the top-seeded, 24-year-old's fourth Grand Slam trophy after making his breakthrough at the 2008 Australian Open.
