Mason, Aug. 14 -- Going small paid off big for Venus Williams.

Tuesday didn't go as well for sister Serena.

On a day when back problems forced the younger Williams to withdraw before her second-round match, Venus Williams reached the third round of the Western & Southern Open with a 6-3, 3-6, 7-6 (4) upset of defending champion Kiki Bertens. Her key? Not going for it.

"I just tried not to go too big, because I can go so big and I have a lot of power and it's not always easy to control it," the 39-year-old Williams said. "So I'm trying to play smart instead of going hog wild, which is extremely easy to do."

Hours before her match was scheduled to begin, Serena Williams withdrew, citing the same back injury that forced her to retire fro...