Heather Watson was forced to pull out of her opening match at the Wuhan Open with illness just days after saying she had fully recovered from the problems which affected her US Open campaign.
The British number two withdrew against American Madison Brengle in China after complaining of dizziness.
British number one Johanna Konta comfortably reached round two after beating German Annika Beck 6-1 6-2.
Ninth seed Konta will play China's Zhang Shuai in the second round.
Konta needs a strong result in the tournament to pass American Madison Keys and Spain's Carla Suarez Navarro in the race to qualify for the WTA Finals later this month, which features the season's top-eight players.