NEW YORK: Rafael Nadal swept into the last 16 at the US Open on Sunday, but Andy Murray`s campaign came to a shuddering halt.

Top seed Nadal swept past Gilles Simon of France 6-4, 6-4, 6-2 as Spanish players dominated the top half of the draw, filling five out of eight places through into the fourth round.

The number one seed will play Spanish compatriot Feliciano Lopez for a place in the quarter-finals. Lopez won through when opponent Sergiy Stakhovsky of Ukraine abandoned when losing 6-3, 4-0.

In earlier play, Spanish eighth seed Verdasco blasted past Argentina`s David Nalbandian 6-2, 3-6, 6-3, 6-2, while compatriot and 10th seed Ferrer ousted compatriot Daniel Gimeno-Traver 7-6 (7/2), 6-2, 6-2.

Those two will meet in the other semi-final in the first quarter of the draw, ensuring at least one Spanish player in the semi-finals.

Tommy Robredo joined them, but in the second quarter of the draw, moving through when French opponent Michael Llodra retired injured when trailing 3-6, 7-6 (8/6), 6-4, 2-1.

Murray had been touted as the main threat to five-times former champion Roger Federer and Nadal following his back-to-back wins over them at the Toronto Masters last month.

But after pocketing the first set in a tie-breaker against Switzerland`s Stanislas Wawrinka, the fourth seed`s game unravelled through a mixture of injury, frustration and his opponent`s fine play.

Wawrinka, who struggled with a thigh injury himself, eventually ran out an upset 6-7 (3/7), 7-6 (7/4), 6-3, 6-3 winner and Murray was downcast after the crushing loss.

"In the third and fourth sets I was struggling physically and I got frustrated with that," the 23-year-old Scot said.

"But I haven`t been in that position for a very long time. Maybe I felt like my chance of doing well here was slipping away.

"I`ve worked very hard to give myself a chance of winning tournaments. When I was struggling physically, I got disappointed.

"But, I`m sorry, that happens. I think it happens to everyone in life at different points."

Nadal had no such problems sweeping past Simon, who could be forgiven for having his mind elsewhere as his first child, a son, was born one month prematurely on Thursday.

"I think I am playing better, a little better, every day," said Nadal, who is bidding here, at 24, to become the youngest player in history to win the Australian, French, Wimbledon and US crowns during his career.

"The serve is still good, so that`s an important thing."

Verdasco, a quarter-finalist here last year, said he had been pushed to the limit early in his match against a fit-again Nalbandian.

"It was four games and 40 minutes in the first set, but I was feeling good physically all the time and I knew I had to be tough to beat a guy like Nalbandian at this moment," he said.

Sam Querrey, meanwhile, boosted US hopes by mastering another Spaniard, 14th seed Nicolas Almagro, 6-3, 6-4, 6-4.

"Hopefully we got someone who can win a Grand Slam - John and Mardy (Fish) and myself - we got a chance," he said of the possibility of a first US winner in New York since Andy Roddick in 2003.

"I feel like I am playing the best I`ve played all summer."

The American, at 22 the youngest man left in the tournament, was untouchable on his own serve and, more suprisingly, he more than matched claycourt specialist Almagro in the extended exchanges.

Isner, the tallest player in the men`s draw at 6 feet 9 inches (2.05metres), was scheduled for the night session on the Arthur Ashe Centre Court against tough Russian Mikhail Youzhny.

BDST: 1334HRS, September 6, 2010