BEIJING, China — Novak Djokovic advanced to the China Open final on Monday after Daniil Medvedev was disqualified late in the second set, when a ball that came off the Russian’s racquet hit a spectator. A man sitting in the stands behind Medvedev’s side of the court was seen holding his face and escorted from his seat after being hit, as Djokovic was serving for the match with the score at 7-5, 5-3. Eleventh-ranked Djokovic will play world...