am Querry of United States of America plays a backhand during his Gentlemen's Singles first round match against Bernard Tomic of Australia on day two of the Wimbledon Lawn Tennis Championships at the All England Lawn Tennis and Croquet Club on June 25, 20
Sam Querry of United States of America plays a backhand during his Gentlemen's Singles first round match against Bernard Tomic of Australia on day two of the Wimbledon Lawn Tennis Championships on June 25, 2013 in London, England.
Credit: Clive Brunskill / Getty Images
It's the first day of the Davis Cup, and the 7,500 Swiss fans are amped. Crimson jerseys are everywhere, white crosses painted on cheeks. They bang on cowbells and blow strange-sounding horns. It feels less like tennis than a Duke–North Carolina game. Mardy Fish shrugs off the distractions and comes from behind to oust Stan Wawrinka in five sets, giving the Americans a 1–0 lead in the series and taking some pressure off John Isner, who's up against Federer next.

No American has beaten Federer since 2008. And no American has beaten him on clay since 1999, when Federer was a teenager. This last fact has been deemed so demoralizing by the managers of the U.S. team that they have decided to keep it a secret from Isner.

The Isner-Federer match begins as expected, with Federer putting away the first set in a mere 29 minutes. The stands convulse redly.

Isner begins to fight back in the second set. He's actually moving pretty well: ­running down balls on the baseline, whacking kamikaze returns off of Federer's serve. The clay was supposed to hurt him: American Kryptonite. Instead it's slowing down the ball just enough to let him get his body in position. Also, the high bounces that clay produces give Isner an edge; the same balls that Federer has to swat down from neck level are sitting up nice and fat for the big man. And then, of course, there's his serve.

At 40–30, serving for the second set, Isner perches on the baseline. He bounces the ball between his legs, an elegant little move that you wouldn't expect from a guy so big. His toss rises to a terrific height. He stretches up to meet it. At the moment of impact a rime of clay explodes from the ball in a red mist. Then the ball comes screaming down the middle of the court on the trajectory of a bomb dropped from a plane. It bounces in, beyond the reach of Federer's forehand, then rockets clear over Federer's head and into the stands.

Isner evens the match at one set apiece, then, shockingly, goes on to kneecap the greatest of all time. Match point comes in the fourth set. On a Federer second serve, Isner leans forward and crushes a backhand return for a winner.

USA 2, Switzerland 0.

The Americans burst onto the clay, clapping, as the stunned, silent Swiss crowd drains out of the arena, into the cold. The on-court interviewer raises a microphone to Isner's face. He says, "Ah, that was, ah, probably, the biggest win of, actually, you know – it was the biggest win of my career." He thanks "all of my teammates there, and especially Captain Courier. He's been on me in practice, tellin' me to do all the right things, and that's what I did today."

The interviewer still can't believe it. She says, "Do you realize . . . you beat . . . Roger Federer?"