New York - Andy Murray was a major casualty at the US Open on Sunday but Rafael Nadal stormed through as did Kim Clijsters and Venus Williams in the women's tournament.
The 23-year-old Scot was out of sorts against Switzerland's Stanislas Wawrinka and his challenge to Nadal and Roger Federer ended in a crushing 6-7 (3/7), 7-6 (7/4), 6-3, 6-3 loss.
"He played better than me. There's not a whole lot more to it," the defeated fourth seed said.
"He had a chance to win the first set; didn't take it. I had a chance to win the second set; didn't take it. I just struggled from then on."
Nadal led a Spanish charge with five of their number making it through to the eight fourth-round slots available in the top half of the draw.
The others were eighth seed Fernando Verdasco, 10th seed David Ferrer, 23rd seed Feliciano Lopez and the unseeded Tommy Robredo.
Nadal takes on Lopez and Verdasco goes up against Ferrer in the first quarter, making it certain there will be at least one Spaniard in the semi-finals.
The top seed was never troubled against France's Gilles Simon, winning 6-4, 6-4, 6-2, and he has yet to drop a set in three matches.
"I am in fourth round. That's good news for me - without losing a set - but there remains a lot to do. I am happy where I am, but is only fourth round," Nadal said.
Others through to the last 16 in the top half were US hope Sam Querrey, who defeated Nicolas Almagro of Spain 6-3, 6-4, 6-4, and Russia's Mikhail Youzhny who edged American John Isner 6-4, 6-7 (7/9), 7-6 (7/5), 6-4.
Wawrinka next plays Querrey and Youzhny takes on Robredo.
In the women's tournament, defending champion Kim Clijsters won the billed match of the day, trouncing former world number one Ana Ivanovic 6-2, 6-1, a victory that was her 18th in a row at Flushing Meadows.
Clijsters was the first player through to the quarter-finals and there she will face Australian fifth seed Samantha Stosur, who ousted Russian 12th seed Elena Dementieva 6-3, 2-6, 7-6 (7/2).
The Belgian second seed said she quickly adapting to the breezy morning conditions on the Arthur Ashe Centre Court.
"With the wind you have to adjust," she said. "I started moving forward, dictating the points better. I was playing good defense as well."
The other quarter-final in the bottom half of the draw sees French Open champion Francesca Schiavone go up against third seed and former champion Venus Williams.
Williams, the last woman to win back-to-back titles here in 2001, saw off a strong early challenge from Israeli 16th seed Shahar Peer before winning 7-6 (7/3), 6-3.
Schiavone topped Russian 20th seed Anastasia Pavlyuchenkova 6-3, 6-0 with her finest display of tennis since winning her maiden Grand Slam title in Paris in June.
Playing against Venus Williams will be a much different prospect for the Italian, however, as she has lost all seven matches they have played to date.
The American, though, said she would not be over-confident.
"We've had some tough matches. She's definitely had some chances to win against me," Williams said. "Obviously her game is better than ever now."
Collated results of Sunday's matches at the US Open tennis championships (x denotes seed):
Kim Clijsters (BEL x2) bt Ana Ivanovic (SRB) 6-2, 6-1
Francesca Schiavone (ITA x6) bt Anastasia Pavlyuchenkova (RUS x20) 6-3, 6-0
Venus Williams (USA x3) bt Shahar Peer (ISR x16) 7-6 (7/3), 6-3
Samantha Stosur (AUS x5) bt Elena Dementieva (RUS x12) 6-3, 2-6, 7-6 (7/2)
David Ferrer (ESP x10) bt Daniel Gimeno-Traver (ESP) 7-6 (7/2), 6-2, 6-2
Fernando Verdasco (ESP x8) bt David Nalbandian (ARG x31) 6-2, 3-6, 6-3, 6-2
Feliciano Lopez (ESP x23) bt Sergiy Stakhovsky (UKR) 6-3, 4-0, retired, right big toe
Sam Querrey (USA x20) bt Nicolas Almagro (ESP x14) 6-3, 6-4, 6-4
Rafael Nadal (ESP x1) bt Gilles Simon (FRA) 6-4, 6-4, 6-2
Tommy Robredo (ESP) bt Michael Llodra (FRA) 3-6, 7-6 (8/6), 6-4, 2-1, retired, dizziness
Stanislas Wawrinka (SUI x25) bt Andy Murray (GBR x4) 6-7 (3/7), 7-6 (7/4), 6-3, 6-3
Mikhail Youzhny (RUS x12) bt John Isner (USA x18) 6-4, 6-7 (7/9), 7-6 (7/5), 6-4