Tennis-Venus upset in last 16 at Charleston

April 7 (Reuters) - Venus Williams' bid for a 50th WTA title ended when she fell to Kazakhstan's Yulia Putintseva in the Round of 16 at the Volvo Car Open on Thursday, while Australian Open champion Angelique Kerber breezed into the last eight. Williams, currently seventh on the WTA's all-time wins list, lost 7-6(5) 2-6 6-4 while German top seed Kerber advanced with a routine 6-2 6-3 win over Slovakian qualifier Kristina Kucova at the clay court event in South Carolina. The loss for third seed Williams extended a disappointing season so far for the seven-times grand slam champion as she arrived on the unique green clay courts of Charleston having lost her opening match in four of five previous events. Williams was plagued by errors during a breezy first set, misjudging a number of volleys and overheads, while Putintseva used her backhand drop-shot to perfection on key points even when pinned deep in the court. Putintseva, who earned her first victory in four career meetings against Williams, will next face either Italian fifth seed Sara Errani or Australian 10th seed and 2010 Charleston champion Samantha Stosur. Germany's Kerber had no trouble with the windy conditions as she recorded 35 winners and converted seven of her 10 break points to get by Kucova in 85 minutes. "I think the feeling is coming back from last year because right now I'm feeling much better on clay again," Kerber told reporters. (Reporting by Frank Pingue in Toronto; Editing by Larry Fine)