Lucie Safarova joined the casualty list of top seeds when the Czech left-hander became the fourth top-10 player to lose in the first round at the US Open.

Sixth-seeded Safarova slipped to a 6-4 6-1 defeat to Ukraine’s Lesia Tsurenko, the woman she beat in the semi-finals in New Haven just last week.

Safarova, the French Open runner-up, joins seventh seed Ana Ivanovic, eighth-ranked Karolina Pliskova and Carla Suarez Navarro, the 10th seed, in failing to get out of the first round.

With world No.3 Maria Sharapova having pulled out of the tournament through injury, only five of the world’s top-10 ranked female players remain in the draw.

World No.2 Simona Halep avoided adding to the list when she reached the second round thanks to New Zealand opponent Marina Erakovic retiring with a knee injury.

Halep was leading 6-2 3-0 when her 99th-ranked rival called it quits.

Romanian 23-year-old Halep goes on to face Kateryna Bondarenko of Ukraine.

“I had a good start. I was aggressive and played my best tennis today,” said Halep, who has yet to get beyond the fourth round in New York.

Fourth-seeded Caroline Wozniacki also avoided the cull of the top seeds by beating American college champion Jamie Loeb, ranked at 413 in the world, 6-2 6-0.

Wozniacki, the 2009 and 2014 runner-up, will face either Christina McHale of the United States or Petra Cetkovska of the Czech Republic for a place in the last 32.

Two-time runner-up Victoria Azarenka, seeded 20, eased past Lucie Hradecka of the Czech Republic 6-1 6-2.