Wuhan - World No 2 Simona Halep suffered a shock exit on Tuesday in her first match at the $2.4 million WTA Wuhan Open, becoming the latest seed to fall in the inaugural tournament.
Halep went crashing out at the hands of Spaniard Garbine Muguruza on a day when four other top players also tumbled.
Tenth-seeded Serb Jelena Jankovic, 11th-seeded Italian Sara Errani, 13th seed Russian Ekaterina Makarova and 16th seed German Andrea Petkovic all fell in the second round.
Just a handful of the sixteen seeds are left in the tournament midway through the second round, with top seed Serena Williams playing her first match later Tuesday.
Eighth seed Caroline Wozniacki suffered a scare in her match against Spaniard Carla Suarez Navarro, before winning at the tie break in the final set.
Romanian Halep has been in fine form in recent months, rising from 11th in the WTA rankings at the start of the year, and being named the second seed at Wuhan.
The 22-year-old opened brightly, taking the first set 6-2, but lost the final two 6-2, 6-3 as Muguruza, who is ranked at 22 by the WTA, became dominant.
The result brought Halep back down to earth after celebrating being named the third player to make the season finale, next month's WTA Championships in Singapore which will feature the top eight women's players.
Elsewhere at Wuhan on Tuesday, Errani crashed out to American Alison Riske 6-4, 6-4, Makarova fell to Timea Bacsinszky of Switzerland 6-4, 6-1, and Petkovic was defeated by Czech player Karolina Pliskova 6-4, 6-4.
Seeds who tumbled on Monday included world number six Agnieszka Radwanska and Czech player Lucie Safarova, who is ranked 15th, who both lost. Ninth-seeded Ana Ivanovic and Australian Open finalist Dominika Cibulkova retired from their matches.
The Wuhan Open in China's central province of Hubei features the world's top 20 women players and reaches its climax on Saturday.Results from the $2.4 million WTA tournament in Wuhan on Tuesday (x denotes seeded player):
Garbine Muguruza (ESP) bt Simona Halep (ROM x2) bt 2-6, 6-2, 6-3
Alison Riske (USA) bt Sara Errani (ITA x11) 6-4, 6-4
Timea Bacsinszky (SUI) bt Ekaterina Makarova (RUS x13) 6-4, 6-1
Elina Svitolina (UKR) bt Sabine Lisicki (GER) 7-6 (7/3), 6-3
Karolina Pliskova (CZE) bt Andrea Petkovic (GER x16) 6-4, 6-4
Kirsten Flipkens (BEL) bt Jarmila Gajdosova (AUS) 6-3, 3-6, 6-3
Coco Vandeweghe (USA) bt Jelena Jankovic (10) 4-1 (Vandeweghe won after retirement from Jankovic)
Barbora Zahlavova Strycova (CZE) bt Madison Keys (USA) 3-6, 6-2, 6-2
Caroline Wozniacki (DEN) bt Carla Suarez Navarro (ESP) 6-1, 3-6, 7-6 (7/4)