Serbian tennis star Novak Djokovic, one of the greatest to ever play the game, was upset at the U.S. Open Friday night. Djokovic fell in the third round with a 6-4, 6-4, 2-6, 6-4 loss to 28th-seeded Alexei Popyrin of Australia.No. 2 seed Djokovic's loss came just one night after No. 3 seed Carlos Alcaraz, who entered the U.S. Open as the favorite to win the tournament, was defeated in the second round."It was just an awful match for me," Djokovic said. "I wasn’t playing even close to my best. It’s not good to be in that kind of state