Novak Djokovic

Novak Djokovic serves during his fourth-round victory over Marcel Granollers at the U.S. Open on Tuesday. (John G. Mabanglo / European Pressphoto Agency / September 3, 2013)

NEW YORK -- Top-seeded Novak Djokovic needed only 79 minutes to advance to the U.S. Open quarterfinals, eliminating Marcel Granollers, 6-3, 6-0, 6-0, in 79 minutes.

Djokovic, who hasn't lost a set yet in the tournament, called his tennis "flawless"  after he won the final 15 games of the match that was once tied at 3-3 in the first set.

Up next for Djokovic in the quarterfinals is 21st-seeded Russian Mikhail Youzhny.

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