‘18 champ Osaka loses to Bencic at US Open; Nadal into QFs

  • Naomi Osaka, of Japan, serves against Belinda Bencic, of Switzerland, during the fourth round of the US Open tennis championships Monday, Sept. 2, 2019, in New York. (AP Photo/Frank Franklin II)

NEW YORK — Naomi Osaka’s achy left knee didn’t let her serve without pain, so she didn’t practice that key part of her game leading into the U.S. Open. The knee also prevented her from covering the court and preparing for shots the way she’d like.