Is Novak Djokovic’s first tennis season without a Grand Slam title in seven years a sign?
NEW YORK — It was the best of times, it was the worst of times. Twenty-six days after Novak Djokovic won Olympic gold in Paris, he finished off his second-least profitable Grand Slam season since 2009 with a stunning third-round defeat to Alexei Popyrin at the U.S. Open. With a few months remaining on the…