Isner even blamed those exuberant attempts to stir the crowd for his struggles down the stretch of a 6-4, 3-6, 7-5, 7-6 (5) loss to 22nd-seeded Philipp Kohlschreiber of Germany.
"I felt like I wore myself out getting charged up out there," Isner said after bowing out against Kohlschreiber in New York for the second consecutive year. "I used too much energy, and I shouldn't have done that. It was stupid on my part. So I was pretty gassed there."
No such concerns about getting tired for Roger Federer. The 17-time Grand Slam champion worked quickly once again, beating 63rd-ranked Adrian Mannarino of France 6-3, 6-0, 6-2 in 1 hour, 21 minutes Saturday night to get to the fourth round in Flushing Meadows for the 13th consecutive year. Through three matches, Federer has dropped 21 games and spent a total of 4½ hours on court.
Next for Federer is 19th-seeded Tommy Robredo of Spain, who ended the run of 179th-ranked qualifier Daniel Evans of Britain 7-6 (6), 6-1, 4-6, 7-5. Win that, and Federer could face 12-time major champion Rafael Nadal in the quarterfinals; the two rivals never have played each other in New York.
Aside from Isner, the other American man in action Saturday, 20-year-old Jack Sock, was beaten 3-6, 7-6 (1), 6-1, 6-2 by No. 18 Janko Tipsarevic of Serbia.
So the last man from the United States left is Tim Smyczek, a 25-year-old from Milwaukee who got into the main draw thanks to a wild-card invitation from the U.S. Tennis Association and plays 43rd-ranked Marcel Granollers of Spain in the third round Sunday. If Smyczek loses a distinct possibility, considering he's ranked 109th and never before even made it past the second round at Grand Slam tournament it will be the first time with zero U.S. men in the round of 16 at the country's tennis championship, which was first played in 1881.
"I don't care," said Isner, who double-faulted to get broken in the last game of the third set, then was broken again while serving for the fourth. "I'm going to watch football for a while. That's all I care about."
A loss by Smyczek also would make 2013 the first season with no Americans in the second week of any of the four major tournaments.
Even if Smyczek wins, it still would be only the second time there was just one American in the fourth round at the U.S. Open. The other? In 2009, when Isner was the lone one in the second week.
All part of the recent decline of American men's tennis.
At Wimbledon this year, for example, no men from the United States even got to the third round. That hadn't happened since 1912 when no Americans entered the tournament.
Then came this news: The ATP rankings of Aug. 12 did not contain a single U.S. representative in the top 20. Never in the 40 years of men's rankings had that been the case.
This edition of the U.S. Open is the 40th Grand Slam tournament since an American man won one of the sport's four most prestigious titles, a record drought that dates to Andy Roddick's 2003 championship in New York. That sort of gap used to be unimaginable for the nation of Bill Tilden and Don Budge, John McEnroe and Jimmy Connors, Pete Sampras and Andre Agassi.
"Well, what shall I say? I think, yeah, it's bad luck," said Kohlschreiber, whose next opponent is Nadal, a straight-set winner Saturday. "For sure, it's not great for the American history not to have a player in the second week. But you had so many good years."
There's a trio of Americans in the women's fourth round, because wild-card entry Alison Riske, who is ranked only 81st, eliminated 2011 Wimbledon champion Petra Kvitova 6-3, 6-0. The seventh-seeded Kvitova got her blood pressure checked by a trainer, then said afterward she had a virus and a fever.
"I've got a new confidence in myself," said Riske, a 23-year-old from Pittsburgh who is now based in College Park, Md. "I believe that I belong here."
There's no doubt the other two U.S. women who are left belong: No. 1 Serena Williams and No. 15 Sloane Stephens play each other Sunday with a quarterfinal berth on the line. Williams is seeking a fifth U.S. Open title and 17th Grand Slam singles trophy overall. Stephens is one of only three women to reach the round of 16 at every major tournament this year, and she beat Williams en route to the Australian Open semifinals.
Riske next faces Daniela Hantuchova, while other fourth-rounders set up Saturday are two-time Australian Open champion Victoria Azarenka against 2008 French Open champion Ana Ivanovic, No. 10 Roberta Vinci against unseeded Camila Giorgi in an all-Italian match, and No. 21 Simona Halep against Flavia Pennetta. The 136th-ranked Giorgi defeated 2009 U.S. Open runner-up Caroline Wozniacki, who was seeded sixth, 4-6, 6-4, 6-3 at night.
Other men reaching the fourth round: No. 4 David Ferrer of Spain, No. 8 Richard Gasquet of France, and No. 10 Milos Raonic of Canada.
Raonic, the highest-ranked man in Canada's history, does not need to worry about the same kind of expectations that players such as Isner do.
"The relief, definitely, is there is obviously a lot more pressure on Americans," Raonic said. "I'm sort of doing a lot of stuff into unchartered territories, so people are very supportive of it, whereas I feel it's a little bit unfair to the American players. Everybody is expecting Pete and Agassi to be there on the top."
P Sunday, 9 a.m.
TV • Ch. 2