Shortly after John Isner helped the Georgia Bulldogs win the 2007 NCAA title, he turned pro at the relatively late age of 22 and was ranked No. 839 in the world.

Just three months later, Isner had improved to No. 184. He reached the third round of the U.S. Open where he met world No. 1 Roger Federer at Arthur Ashe Stadium.

"I've certainly played a lot of matches in my career," Isner, 30, says. "That's certainly one that sticks out. I was completely unknown coming out of college. I got to play against Roger when he was really in his prime. He was No. 1 in the world by a mile and he wasn't losing to anyone."

John Isner

On national television, on center court, the 6-10 Isner took Federer by surprise and nabbed the first set in a tiebreaker.

"I didn't win many games after that, but it was a great experience," Isner says.

Federer won the next three sets (and later, his fourth of five consecutive U.S. Opens), but he tipped his hat to Isner, saying, "I think he's always going to be tough to beat because of that serve. That serve is not going to go away anytime soon."

John Isner Fist Pump

After a notable third-round win against Andy Roddick in the 2009 U.S. Open, Isner continued to move up the rankings. In April 2012, Isner became the top-ranked American, a title he has held the majority of time since. This is Isner's fourth-consecutive U.S. Open as the highest-ranked American.

"It's something I never thought could be possible for me," Isner says. "It's something I was never tapped or pegged or picked to be the next good American player. I take it in stride. It's all very surprising to me."

Isner does not look like a traditional tennis player. He has the body of a basketball player, wears backwards hats and strays from tennis to talk about Georgia football.

"I think they're going to be good," he says of the Bulldogs' 2015 season. "If you can run the ball like Georgia can, their offensive line, they returned everyone, they got a running back in Nick Chubb."

Isner calls his American standing an "honor," but he also says he is a "realist." American tennis is far from the days of names like Pete Sampras, Andre Agassi, John McEnroe and Jimmy Connors, let alone Roddick and James Blake.

John Isner And Roger Federer

"If I was No. 13 in the world (current ranking and U.S. Open seed) in the 1990s or early 2000s, I'd be the fourth-highest ranked American, but that's really none of my concern," Isner says. "I can't control what anyone else does, but I'm very proud to be the top-ranked American."

Isner currently heads a U.S. crop with only one other player seeded at the U.S. Open, No. 28 Jack Sock. Sam Querrey is the world No. 38 and Steve Johnson is No. 47.

"Now that I am the No. 1 American, I expect to be the No. 1American for this year and next year and the year after," says Isner, who participated in American Express's Rally On The River before the U.S. Open.

His accomplishments are not Hall of Fame level, but they garner respect. He reached a quarterfinal at the 2011 U.S. Open, and Isner has made the fourth round at four majors. In April 2012, he reached a career high ranking of No. 9.

He also beat Federer once in five tries. In a 2012 Davis Cup match against Switzerland, Isner disposed of Federer in four sets. This time around, it was Federer winning the first set before Isner took the next three.

John Isner Serve

In other news, Isner is hoping Georgia wins its ivalry game this year:

"On paper, they should beat Florida," says Isner, who witnessed the Gators upset the Bulldogs a year ago. "Over the last 20 years, Florida has really dominated. Hopefully, Georgia can turn the tide a bit."

In Athens, the Bulldogs have a hungry fan base waiting for Georgia to compete for a national title again. In Flushing Meadows, American men's tennis fans are rooting for Isner to be a light in otherwise dim decade for the sport in the U.S.

Isner's journey starts Tuesday with No. 81 Malek Jaziri of Tunisia.

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-- Follow Jeffrey Eisenband on Twitter @JeffEisenband.