Venus powers past Riske; Bencic toppled

Williams, seeded third and seeking a 50th career WTA title this week, fired 20 winners, displaying a sharp service game in a match lasting less than 90 minutes. 

Things didn’t go so well on the green clay of Charleston for second-seeded Swiss Belinda Bencic, beaten 6-1, 6-1 by Russian Elena Vesnina. 

Spain’s Dominguez was leading 6-4, 1-6, 1-0 when Bouchard decided she couldn’t continue. 

Williams next faces Kazakhstan’s Yulia Putintseva for a place in the quarter-finals.

Putintseva defeated 15th-seeded German Sabine Lisicki 7-5, 4-6, 6-3. 

In other matches on Wednesday, seventh-seeded American Sloane Stephens defeated Danka Kovinic 6-4, 6-3, but former Charleston finalists Lucie Safarova and Madison Keys both bowed out. 

America Louisa Chirico sent fourth-seeded Safarova packing 6-3, 6-3, while Germany’s Laura Siegemund rallied for a 6-7 (3/7), 6-4,6-4 win over eighth-seeded Keys.