Osaka advances at US Open as opponent withdraws

Naomi Osaka has advanced to the third round of the U.S. Open after her second-round opponent withdrew for medical reasons.

The defending champion was set to play Olga Danilovic of Serbia in the first match of the day in Arthur Ashe Stadium.

The U.S. Tennis Association said the match between women's No. 12 seed Simona Halep and Kristina Kucova would move to Ashe.