When it came time Tuesday to prepare for their all-Williams quarterfinal at the U.S. Open, the sisters lined up on adjacent courts, hitting beside -- not with -- each other. They often practice together. Not this time. Not with what's at stake Wednesday night in their 17th meeting as professionals. Their father, who along with their mother coaches both women, went back and forth, keeping tabs on his racket-wielding daughters. Later, the side-by-side training sessions done, the sisters caught separate rides away from Flushing Meadows. As Serena walked alone to the parking lot, checking for text messages on her pink cell phone, she was asked if it becomes less tough to have to look across the net during a match and see Venus standing there. "It does," Serena said Tuesday. "Each time, it gets easier."