World number three Maria Sharapova retired with an arm injury in her comeback match at the Wuhan Open in China.
The 28-year-old Russian, returning from a leg problem, led Czech Barbora Strycova 7-6 (7-1) 6-7 (4-7) 2-1.
It was Sharapova's first match since she lost to Serena Williams in the Wimbledon semi-finals in July.
"I got pain in my left forearm. It just got worse and worse as I continued," said Sharapova.
"I just don't think it's smart to continue trying to run around the court and trying to hit forehands from the backhand side and compensate other things.
"I haven't played a match in many months. I guess this is the consequence of that. I just have to work on getting it better."
The five-time Grand Slam champion was returning from the leg injury which forced her to miss the American hard-court season and the US Open.
She is scheduled to play in Beijing next week, but has made next month's WTA Finals in Singapore and Russia's Fed Cup final against the Czech Republic in November her major targets for the rest of the year.
"Singapore and the Fed Cup is a big priority," she said. "I'll do everything in order to be healthy for that.
"I don't know how long it will take for this to recover so I can't really give a definite answer about next week."