British number one Heather Watson lost in straight sets to 16th seed Venus Williams in the China Open first round.
Watson had been hoping to find some form after first-round exits at her three previous tournaments.
But after racing into a 3-0 first set lead, the 22-year-old lost 11 straight games in a 6-3 6-1 defeat.
"Heather was playing really well. The first games she didn't miss a serve for six points. I give her a lot of credit," said American Williams.
Watson reached a career high of 39 in the world last year before being struck by glandular fever, but she moved back into the top 50 after reaching the last 16 of the Montreal Open in August.
She has now lost in the opening round of four consecutive events, following defeats by world number 80 Sorana Cirstea at the US Open, qualifier Nicole Gibbs, the world number 101, at last week's Korea Open, and world number 12 Sara Errani of Italy at the Wuhan Open.
The 34-year-old Williams, who suffered a surprise first round defeat at the WTA Wuhan Open last week, will face 12th seed Ekaterina Makarova in the second round.
Elsewhere in the first round, second seed Simona Halep beat Barbora Zahlavova Strycova 6-1 6-4 and fourth seed Maria Sharapova beat Kaia Kanepi 6-4 6-1, while Japan's Kurumi Nara overcame 11th seed Errani 3-6 6-3 6-4.
Australian Samantha Stosur beat Francesca Schiavone 6-4 6-2 to set up a second-round clash against former world number one Caroline Wozniacki who is eyeing a spot in the year-ending WTA FInals in Singapore.