Host country favorite Naomi Osaka advanced to the second round of the Toray Pan Pacific Open on Tuesday as her Australian opponent Daria Saville had to retire early in the first set with a knee injury.Saville fell to the court in pain after hitting a forehand in her first service game at Tokyo's Ariake tennis park. It happened after defending champion but unseeded Osaka, ranked 48th in the world, held her serve in the opening game.The former world No. 1 and winner of four Grand Slam singles titles will next face fifth-seeded Brazilian Beatriz Haddad Maia, the 6-4, 6-2 winner over Yuki Naito…READ FULL ARTICLE