Former world number one Venus Williams' attempt to win her 50th WTA title at the Volvo Car Open ended when she lost to Kazakhstan's Yulia Putintseva.
The 35-year-old American lost 7-6 (7-5) 2-6 6-4 in the last 16 in Charleston.
Putintseva's victory over the third seed, who is seventh on the WTA's all-time wins list, set up a quarter-final with Italy's Sara Errani.
It was the first time the 21-year-old had beaten Williams in four career meetings.
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