New York: Second seed Simona Halep reached the US Open second round on Tuesday when New Zealand opponent Marina Erakovic retired with a knee injury.
Halep was leading 6-2, 3-0 when her 99th-ranked rival called it quits, having received a medical timeout for treatment on her right knee at the end of the first set.
Romanian 23-year-old Halep goes on to face either Kateryna Bondarenko of Ukraine or Yulia Putintseva of Kazakhstan for a place in the last 32.
"I had a good start. I was aggressive and played my best tennis today," said Halep.
"I know I can play my best tennis here. I have no expectations. Serena is there. I just want to play my best tennis."