Roddick cruises into last eight in US Open tune-up

Fit-again Andy Roddick kept his US Open preparations on a smooth track by crushing Colombian Santiago Giraldo 6-1, 6-3 in the third round of the Winston-Salem Open on Wednesday.

The top-seeded American, whose buildup to the season's final Grand Slam had been interrupted by an abdominal injury, showed no signs of rust as he eased to victory in just over an hour to book his place in the last eight.

Roddick, the 2003 US Open champion, will next meet seventh-seeded Argentine Juan Monaco who hammered Japan's Kei Nishikori 6-0, 6-3.

In other matches, fourth-seeded American John Isner powered past Finland's Jarkko Nieminen 7-6, 6-2 while third seed Alexandr Dolgopolov of Ukraine had to work hard for a 6-4, 1-6, 7-6 victory over 14th-seeded Bulgarian Grigor Dimitrov.

"It took me a while to get used to how he was playing," the big-serving Isner said. "From 4-4 in the tie-break, that's when I really kicked up. I was kind of on my way from there.

'I held serve comfortably today and that just puts so much pressure on my opponents. I'm very fortunate to have my serve."

Ninth-seeded Ukrainian Sergiy Stakhovsky pulled off the biggest surprise in the third round, upsetting fifth seed Nikolay Davydenko of Russia 6-4, 6-4.