Czech top seed Tomas Berdych and Wimbledon semi-finalist Milos Raonic advanced while US fifth seed John Isner lost Wednesday in second-round matches at the ATP and WTA Washington Open. (Some 'licking their chops' at Nadal's possible US Open absence, says Raonic)
Berdych, seeking his 10th career ATP title and first on US soil, defeated US qualifier Robby Ginepri 6-1, 6-4 at the $1.9 million (1.4m euro) hardcourt tune-up for the US Open.
Canadian second seed Raonic fired 16 aces in ousting American Jack Sock 7-6 (7/3), 7-6 (7/3) while American Steve Johnson never faced a break point and withstood a 29-ace barrage to defeat countryman Isner 6-7 (5/7), 6-3, 7-6 (8/6).
And Japan's fourth-seeded Kei Nishikori outlasted American Sam Querrey 6-4, 5-7, 6-4 to join them in the last 16.
Berdych connected on only 48 percent of his first serves but still needed only 68 minutes to dispatch Ginepri, whose only two ATP wins this year came in the past 10 days, and book a third-round date with Canada's Vasek Pospisil.
"I felt good on the court," Berdych said. "My goal was from the first point try to be focused. It can be tougher after you have a few weeks off."
Raonic, coming off a loss to Roger Federer in his first Grand Slam semi-final, advanced to a third-round match with 33-year-old Australian Lleyton Hewitt, the 2001 US Open and 2002 Wimbledon champion.
"Felt good and didn't feel so good," Raonic said. "You have to understand yourself and not expect to play your best tennis."
Sock seized a 3-1 edge in the first tie-breaker but Raonic answered by winning the next six points to claim the opening set, the last coming when Sock netted a forehand.
"I'm hahappy was able to come back," Raonic said.
Sock served for the second set in the 10th game but Raonic broke back and reached another tie-breaker that went to 3-3. Raonic swept the next four points, the last on a forehand winner for the victory in one hour 42 minutes.