After waiting out that nearly 4 1/2-hour match, Venus Williams defeated French Open champion Francesca Schiavone of Italy 7-6 (5), 6-4 to reach her first Grand Slam semifinal since last year's Wimbledon.
Wawrinka won 7-6 (9), 6-7 (5), 7-5, 4-6, 6-4 on Tuesday to join a countryman whose presence this deep in a major tournament is just assumed: Roger Federer. Not so for Wawrinka. The 25-year-old had been 0-5 in the round of 16 at Grand Slams.
"Roger, he's always in quarterfinals since many years, so that's not something different," Wawrinka said. "But for me, it's my first time, so it's something important for my career."
The US men, meanwhile, had at least one quarterfinalist at their home major each of the first 41 years of the Open era. That changed in 2009, and now it's happened again.
Querrey himself is still searching for his first Grand Slam quarterfinal berth. He had his chances. So did the 25th-seeded Wawrinka, as momentum swung back and forth as quickly as the wind whipped around Arthur Ashe Stadium.
Williams, seeded third, and the sixth-seeded Schiavone struggled to hold serve: There were nine breaks in 23 games. Williams failed to serve out the match in the second set, then proceeded to break the Italian to clinch the victory.
"It's not easy to play in these conditions," Williams said. "It's hard to know what decisions to make."
No. 20 Querrey wasted three break points in the third game of the final set, which seemed headed to another tiebreaker until Wawrinka made one final push leading 5-4.
Querrey fought off one match point with a lob that was just high enough to force deuce. But after Querrey hit a forehand into the net, Wawrinka made the most of his second chance.
This goes down as the worst year for American men in Grand Slam events. They had only one quarterfinalist at the four major tournaments: Andy Roddick at the Australian Open.
In the first two sets, each player went up 3-0 to start a tiebreaker only to go on to lose it.
Querrey was fortunate to even be in that second tiebreaker after saving four set points at 4-5. He appeared to be in control in the third set, going up a break, but Wawrinka rallied to break him twice and close out the set.
The youngest man left in the draw, the 22-year-old Querrey was in the midst of a breakthrough season, reaching the fourth round at a second straight Grand Slam. He entered the top 20 in the rankings for the first time in July and had won four titles this year; only No. 1 Rafael Nadal has more.
With Wawrinka upsetting fourth-seeded Andy Murray in the third round, the draw seemed to be opening up for Querrey to make a deep run. His quarter of the bracket didn't have a top-10 seed left.
In contrast, Wawrinka didn't come into the Open looking like a future quarterfinalist. A former top-10 player, his ranking had slipped to No. 27, the lowest in more than two years.
But Wawrinka had the experience of a 13-7 record in five-set matches. Querrey was just 1-2.
Wawrinka will next face Mikhail Youzhny, who briefly slowed Spain's march through the U.S. Open bracket.
The 12th-seeded Russian beat Tommy Robredo, the lowest-ranked man left in the draw, 7-5, 6-2, 4-6, 6-4. The 41st-ranked Robredo was one of a record six Spanish men to reach the fourth round at Flushing Meadows.
Two will make the quarters: No. 1 Rafael Nadal faced 23rd-seeded Feliciano Lopez and eighth-seeded Fernando Verdasco took on No. 10 David Ferrer in a pair of all-Spanish matchups later Tuesday.
"They have a lot of courts. They have a lot of good facilities to practice well," Youzhny said. "I think it's not really expensive to practice in Spain for Spanish people. In Russia now it's much expensive to practice in Moscow. Not everybody can do this one."
Williams will next face the winner of Tuesday's second women's semifinal: No. 2 Kim Clijsters, the defending champion, against No. 5 Sam Stosur.
