NEW YORK (AP) - Novak Djokovic was kicked out of the U.S. Open for accidentally hitting a line judge in the throat with a tennis ball after dropping a game in his fourth-round match Sunday, a stunning end to his 29-match winning streak and bid for an 18th Grand Slam title. As he walked to the Arthur Ashe Stadium sideline for a changeover, trailing Pablo Carreno Busta 6-5 in the first set, Djokovic - who was seeded and ranked No. 1 and an overwhelming favorite for the championship - angrily smacked a ball behind him. The ball flew right at the line judge, who dropped to her knees at the back of the court and reached for her neck. During a discussion of about 10 minutes near the net involving chair umpire Aurelie Tourte, tournament referee Soeren Friemel and Grand Slam supervisor Andreas Egli, Djokovic appeared to be pleading his case. But eventually, he walked over to shake hands with Carreno Busta. Tourte then announced that Djokovic was defaulted, the tennis equivalent of an ejection. "I was a little bit in shock, no?" Carreno Busta said later at a news conference done via video conference. Djokovic quickly left the tournament grounds without speaking to reporters, posting an apology on social media hours later. "This whole situation has left me really sad and empty. I checked on the lines person and the tournament told me that thank God she is feeling ok. I'm extremely sorry to have caused her such stress. So unintended. So wrong," Djokovic wrote. "As for the disqualification, I need to go back within and work on my disappointment and turn this all into a lesson for my growth and evolution as a player and human being," he wrote. "I apologize to the @usopen tournament and everyone associated for my behavior." Asked whether Djokovic should...