NEW YORK (AP) An American man playing at the American Grand Slam tournament, John Isner found it hard to believe so many U.S. Open spectators were cheering so vigorously for his French opponent, Gael Monfils.
They clapped rhythmically while chanting, "Let's go, Monfils!" They loudly sang his last name between points. They rose to their feet and raucously saluted Monfils' best shots. They applauded faults and other miscues by the 13th-seeded Isner, the highest-ranked U.S. man, who eventually pulled out a 7-5, 6-2, 4-6, 7-6 (4) victory Thursday night.
"I was a little bit disappointed in that, actually. Not going to sugarcoat it," said Isner, who reached the third round at Flushing Meadows for the fifth consecutive year. "If I was playing in France, it certainly wouldn't be like that."
From late in the third set, spectators at Louis Armstrong Stadium really began backing Monfils.
"It was surprising, actually," Monfils said. "It was surprising - but it was good."
Certainly was an unusual display during a match involving a U.S. player at the most important tennis tournament in the United States. Maybe, as Monfils guessed afterward, the ticket-holders simply wanted more bang for their buck, instead of a three-set, open-and-shut affair. Or maybe, as Isner surmised, Monfils' style just won them over.
"He's a very fun-loving guy, and he gets cheered on wherever he goes, not just in France. He's one of the most exciting tennis players in the world, hands down," Isner said. "He's been fighting a bunch of injuries, so it's good to see him back healthy."
Monfils is most decidedly a showman, one of the most gregarious and demonstrative players on tour, one who plays to the crowd and sometimes seems more interested in being an entertainer than a winner. He's been ranked as high as No. 7, and reached the semifinals at his home major, the French Open, in 2008. But he also has been slowed by injuries, and skipped Wimbledon this year.
Monfils did not disappoint Thursday, sliding into the splits while chasing some balls, holding his arms wide apart and nodding after one particularly skillful shot, and even pointing out a man in the stands who was chastised by the chair umpire for using a flash while taking photos.
"He gets the crowd involved," Isner said. "If you purchase a ticket to watch him play, you're not going to go home disappointed. That's just how it is."
The 6-foot-10 Isner, born in North Carolina and based in Florida, is hardly the most well-known or accomplished U.S. tennis player, but he is probably the host country's best chance for a deep run this year. Especially after the next-highest U.S. man, 26th-seeded Sam Querrey, lost earlier Thursday to Adrian Mannarino of France 7-6 (4), 7-6 (5), 6-7 (5), 6-4.
Now Isner will face No. 22 Philipp Kohlschreiber of Germany, the player he lost to in the third round last year.
"I'm going to get some revenge on him," said Isner, whose best showing at any Grand Slam tournament was when he was a quarterfinalist at the 2011 U.S. Open.
What he is most famous for, of course, is winning the longest match in tennis history, an 11-hour, 5-minute marathon that stretched over three days at Wimbledon three years ago before ending at 70-68 in the fifth set.
One thing Isner does rather well is win tiebreakers, thanks in large part to his booming serve, and that was how this match was decided.
Monfils was ahead 4-3 in the fourth-set tiebreaker, but Isner took the last four points. He hit a 135 mph service winner, then a 139 mph ace - his 23rd of the match - to make it 5-4. An inside-out forehand winner put Isner up 6-4, earning a match point, and he gestured to the fans to show him some love.
They did, screaming, "U-S-A! U-S-A!"
Isner - whose right hip was bothering him and was treated by a trainer early in the fourth set - ended it there, hitting a crisp volley that Monfils got to, but could only put into the net. Isner chucked his racket and then pantomimed the same sort of "Superman"-inspired move that Cam Newton - the quarterback for Isner's favorite NFL team, the Carolina Panthers - uses to celebrate touchdowns.
"I ... knew that against Gael, the atmosphere was going to be electric," Isner said, "and that's what it was."
Follow Howard Fendrich on Twitter at http://twitter.com/HowardFendrich