There was one final stab for Sam Querrey, a lunge to his right that allowed his racket to barely connect with the ball and send it high up into the cloudless sky. Once there, the ball seemed to hang like an open parachute, just waiting for Rafael Nadal to cock his arm behind his head and slap down an overhead smash to end their spirited fourth-round match at the US Open 6-2, 5-7, 7-6, 6-3.

For the first set and a half of what turned out to be a three-hour, 13-minute chariot race yesterday, Querrey, a 20-year-old Californian who had won just one match in two previous US Opens, looked every bit the footman to King Rafa, the world's No. 1. The forehand that would have sent his former junior foes scrambling side to side and the serves that might have had them cowering in the corners looked positively plebeian to Nadal.

Everything Querrey did, Nadal simply did better, from his court coverage to the backhand drop shot that died just over the net, helping the Spaniard win the first set in just more than a half-hour and setting the stage for what looked to be a quick afternoon.

"The first set, I was kind of nervous," said the 55th-ranked Querrey, who reached the round of 16 at a major for the first time and took home $80,000 for his efforts. "My first time on Ashe, and it was pretty windy at the beginning. It was windy and my heart was racing for the first hour."

But with Nadal up by a set and 5-3 in the second, Querrey, buoyed by four shirtless friends from California who flew in on a red-eye to support him and called themselves "Sam-urai Warriors," quelled his nerves, amped up his serve and inside-out forehand, and broke Nadal twice while winning four straight games to even the match.

"It was difficult, no?" said Nadal, who has won 42 of his last 43 matches - and six of his last seven tournaments. "I had the match under control, no?"

After squandering yet another break of serve in the third set, Nadal showed his natural agility and versatility, taking the tiebreaker with relative ease. When he saved seven break points to hold serve in a 15-minute seventh game of the fourth set, the match, in effect, was over.

 It was clear to me that Nadal , who already didn't seem at his best on Saturday when he beat Troicki, won this match because of Querrey's bad mistakes at the worst possible time. The top seed just hang in there and fought every ball he could but coudln't serve well (Was 49% on his second serve which is low for his standards) and made many errors with his favorite shot , the forehand.

Maybe the Spaniard is starting to feel the exhaustion after everything he just achieved (winning French Open, Queen's, Wimbledon, Canadian Masters, Gold medal at the Olympics) . The question is will he have enough steam to reach his first US Open final? We hope so for the beauty of the game but I'm starting to have my doubts.

Nadal, who has reached the quarter-finals at the Open for only the second time in six years - he has never reached the semifinals - will face unseeded American Mardy Fish, who continued his upset run with a 7-5 6-2 6-2 demolition of 32d-ranked Gael Monfils of France.

The other quarterfinal in Nadal's half of the draw will feature 17th-seeded Juan Martin del Potro of Argentina and sixth-seeded Scotsman Andy Murray. Murray took care of 10th-seeded Stanislas Wawrinka, 6-1 6-3 6-3. Del Potro knocked out 18-year-old Kei Nishikori of Japan, 6-3 6-4 6-3. Del Potro has won 23 straight matches, the longest active win streak on the ATP Tour.

rom the moment the US Open draw was released, revealing Venus and Serena Williams to be likely quarterfinal opponents, the sisters have played as if on a mission to reach each other. The meeting was arranged with astounding ease as the seventh-seeded Venus trounced No. 9 Agnieszka Radwanska, 6-1 6-3, and fourth-seeded Serena needed just one hour to dismantle French wild card Severine Bremond 6-2 6-2.

The other section of the women's draw will feature a quarterfinal between the No. 6 seed, Russian Dinara Safina, and No. 16, Flavia Pennetta of Italy. Safina beat German qualifier Anna-Lena Groenefeld, 7-5 6-0, while Pennetta ousted former world No. 1 Amelie Mauresmo of France, 6-3 6-0.

"Yeah, it [stinks]," Serena said candidly of the prospect of facing her sister so early in the tournament. "But at least it means that one of us will be in the semifinals."

The sisters have faced each other 16 times over the last decade (not including a walkover win for Serena in Indian Wells, Calif., in 2001 when Venus claimed she was injured) and each has won eight times. Ten of those meetings have been in majors and seven have been in finals, including at Wimbledon this past July, where Venus won her fifth championship with a 7-5 6-4 victory.

This is their fourth meeting at the US Open, including back-to back finals in 2001 and '02. Venus won in '01 and Serena won the following year. Neither has been back to the finals here since. The last time they met here, in the Round of 16 in 2005, Venus won in straight sets.

"I would love to win this championship," said Venus, who has dropped just 15 games in four matches thus far (Serena has lost just 14). "That will be a huge milestone to get by her to win this championship. That's pretty much how I see it, as trying to win the tournament.

"I think if I had a sister and she wasn't very good, then it would be just not really a big deal because I would beat her. But she's very good, so I have to figure out, OK, how can I win this match?"