NEW YORK -- Any time now, Andy Murray will break through and become Britain's next Grand Slam champion.
Or so the theory goes.
The fourth-seeded Murray, expected by many to make a deep run at this year's U.S. Open, instead made his second straight earlier-than-expected exit from Flushing Meadows -- losing to No. 25 Stanislas Wawrinka on Sunday in the third round.
Wawrinka rallied from a break down late in the second set for a 6-7 (3), 7-6 (4), 6-3, 6-3 upset -- a loss certain to be picked apart by the tennis-loving fans back home.
"I have no idea of whether I'll win a Grand Slam or not," Murray said. "I want to. But if I never win one, then what? If I give 100 percent, try my best, physically work as hard as I can, practice as much as I can, then that's all I can do."
Murray is trying to become the first British man to win a Grand Slam tournament since 1936. He was a popular pick this year, based on trips to the finals at Flushing Meadows two years ago and this year's Australian Open, along with a championship in Montreal last month in which he beat both Rafael Nadal and Roger Federer.
Wawrinka's upset was the only significant surprise on a day that saw the top-seeded Nadal and four other Spaniards advance: No. 8 Fernando Verdasco, No. 10 David Ferrer, No. 23 Feliciano Lopez, and unseeded Tommy Robredo.
"Probably the most difficult tournament for us, no?" Nadal said after beating Gilles Simon of France 6-4, 6-4, 6-2. "So that is very important news for Spanish tennis."
Murray alone bears the burden of Britain's hopes for its first male Grand Slam champion since 1936. He was a popular pick to go far at Flushing Meadows; he was the runner-up at the 2008 U.S. Open and at this year's Australian Open, also on hard courts.
The promise of a deep run this year for Murray slipped away quickly after the second set. The 23-year-old Scot needed the trainer twice after that -- once for tightness in his quad, another when he felt tingling in his right elbow.
But he didn't blame the injuries.
"He played better than me," Murray said. "There's not a whole lot more to it."
He served poorly against Wawrinka, putting only half of his first serves in and getting broken eight times. Now Wawrinka will attempt to solve the serve of 20th-seeded American Sam Querrey, who hit 19 aces at up to 137 mph and never was broken by 14th-seeded Nicolas Almagro on Sunday.
Querrey beat Almagro of Spain 6-3, 6-4, 6-4.
"He's very dangerous on this surface," Almagro said. "He's in top form right now."
At the 2009 U.S. Open, zero U.S. men reached the quarterfinals for the first time in the history of an event that began in 1881. This time, of 15 Americans that entered the tournament, there are two who are still around for the fourth round -- Querrey and No. 19 Mardy Fish -- after No. 18 John Isner lost to No. 12 Mikhail Youzhny of Russia 6-4, 6-7 (7), 7-6 (5), 6-4 despite hitting 33 aces Sunday night.
Isner, best known for winning the longest match in tennis history at Wimbledon in June, got broken early in each of the first two sets, then was down 5-1 in the second, before making things interesting. But Youzhny came up with one of his five aces to end the third-set tiebreaker, then broke the 6-foot-9 Isner again early in the fourth. Youzhny heads to the U.S. Open's fourth round for the first time since he was a semifinalist in 2006.
Isner said he didn't think he paid any price physically at Flushing Meadows for all the wear-and-tear his body took at the All England Club during the longest match in tennis history.
"I don't think tonight had anything to do with that match, I would say," Isner said.
What Isner did concede might have hampered him was injuring his right ankle last month during a hard-court tournament in Cincinnati.
"I'm not the fastest guy out there, but I didn't feel as explosive. My legs I think just didn't have the bend that I needed to on my serve, on my groundstrokes," he said. "I mean, I wasn't dealt the greatest hand coming into this tournament with really no preparation. So that maybe had something to do with it."
The 6-foot-9 Isner lost Sunday despite pounding 33 aces at up to 144 mph.
"Of course, you understand [there] will be aces," Youzhny said of facing Isner. "But [here's the] main point: If you have some chances, try to take these chance, because [there] will not be too many chances."
Fish won Saturday to earn a spot in the fourth round, where he will take on No. 3 Novak Djokovic of Serbia.
When Andy Roddick -- the American who won the 2003 U.S. Open -- briefly dropped to 11th in August, it was the first time since the rankings began in 1973 that there were no U.S. men in the top 10. That alone was enough to cue a new chorus of questions about the state of the game in a nation that produced Pete Sampras and Andre Agassi, Jimmy Connors and John McEnroe.
"I mean, you always hear that," said Querrey, who grew up in California but now lives in Las Vegas. "It's kind of like any sport. You've got waves where you'll have a group of Americans in the top 10; you might have a couple years where we don't. It's like with the Lakers: They'll win some championships, and [then] they won't make the playoffs. It's just like that."
With Sunday's five Spaniards joining No. 21 Albert Montanes, who won Saturday, that country has six members of the last 16 -- tying the record for a country other than the United States at the U.S. Open.
"It's always nice to see all the Spanish winning and being in the last rounds, no?" said Verdasco, who eliminated 2002 Wimbledon runner-up David Nalbandian of Argentina 6-2, 3-6, 6-3, 6-2.
Ferrer beat Daniel Gimeno-Traver of Spain 7-6 (2), 6-2, 6-2; the opponents of Robredo and Lopez retired during their matches. The winners of Nadal vs. Lopez, and Ferrer vs. Verdasco will meet for a semifinal spot.
"I don't really care whom I'm playing against," Nadal said, "if they're all Spaniards."
Information from The Associated Press was used in this report.