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.