Rafael Nadal kept his perfect record intact at the US Open Tuesday as he powered past Spanish compatriot Feliciano Lopez into the quarterfinals.

The top seed won 6-3, 6-4, 6-4 and in four outings to date he has yet to drop a set or even his serve.

Next up in his sights is old foe Fernando Verdasco, another Spaniard against whom Nadal has a perfect 10-0 win-loss record.

" I was ready for the late start and the hardest thing was for the fans to be here," he said.

"This year I am healthy and hope to continue to play well and have my chances."

Verdasco took four hours 23 minutes to see off compatriot David Ferrer in a typically gruelling Iberian clash that involved merciless, end-to-end tennis.

"I hope that it is going to give me big confidence, this match," the eighth seed said.

"And also I hope to be 100 per cent physically after a tough match like today to play

against a player like Nadal that you need to be like 100 per cent to try to face him, to try to beathim."

Home hopes, meanwhile, were blown away by Switzerland's Stanislas Wawrinka when he outlasted Sam Querrey in a marathon fourth round tie.

The 7-6 (11/9), 6-7 (5/7), 7-5, 4-6, 6-4 defeat means that

there will be no US player in the men's singles quarterfinals for thesecondyearina row.

Last year was the first time that had happened in the Open era dating back to 1968.

The 20th-seeded Wawrinka joins Roger Federer in the last eight, making it the first time two Swiss players have reached the quarterfinals of a Grand Slam in the Open era.

The match, played in tough, windy conditions, lasted four hours 28 minutes.

"I think for sure the crowd was hoping that he can stay in the tournament. But if you watch the match they were very fair. For me it was great to play that kind of match with that crowd,” the 25-year-old Wawrinka said after reaching his first Grand Slam quarterfinal.

His opponent for a place in the semifinals will be 12th-seeded Russian Mikhail Youzhny, who defeated Tommy Robredo of Spain 7-5, 6-2,4-6,6-4.