Novak Djokovic grinded through physical and internal ailments, made one mistake after another and could not find what it took to beat a feisty, younger opponent who was not intimidated under the lights against tennis' most decorated player.

The 39-year-old is out of the U.S. Open after a first-round defeat to Mariano Navone on Sunday night, losing 7-6 (5), 5-7, 4-6, 6-2, 6-1 in a five-set marathon that lasted four hours and 36 minutes. It was the longest opening match of a Grand Slam in Djokovic's career and became his earliest exit in one in two decades, dating to the 2006 Australian Open. He had never lost in the first round at the U.S. Open.