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
I'm riding in a black van through the Swiss countryside, on the way to watch the first U.S. practices of the week and try to figure out how American tennis fell behind and what's being done to catch up. Sitting behind me are the two youngest players on the team: John Isner, 26, and Ryan Harrison, 19. We pass cow pastures, creeks, and quaint towns. We see signs pointing to Basel, birthplace of Roger Federer.

Harrison asks Isner, "How do you feel out on this court? I feel like shit."

"Courier is on my ass," Isner says. "If I don't groove it 100 percent, he's on my ass."

After several minutes, the van pulls up to a large glass-fronted building in the city of Fribourg. Inside is a 7,500-seat arena with a single red-clay tennis court. In Davis Cup, the home team picks the court surface, and the Swiss choice is intended to frustrate the Americans, who tend to lose their bearings on slower, lumpier clay. According to one tennis blog that has predicted a Swiss shutout this week, clay is "American Kryptonite."

Two Americans are trading ground strokes: Fish – a wily veteran who spent most of his career in Roddick's shadow, only to surpass him last year after losing 30 pounds – and a scrawny junior the team has brought along as sort of a whipping boy. Harrison and Isner take seats courtside and watch Mardy Fish try to get used to the surface.

"This is Bjorn Fratangelo," Tim Curry, the head of corporate communications for the USTA, tells me, pointing to the kid. "He was the first American to win the French Open Juniors since McEnroe."

"So he's a clay-court specialist?" I ask.

Curry cracks a smile. "As much as any American can be."

Between points, Fish smooths piles of clay with his feet and smacks his racquet against his shoes, sending clumps of red flying. He does this over and over, as if the clay were some kind of toxic pudding. After a few minutes, Fish's young hitting partner takes a seat, and Courier walks onto the court with a cardboard box full of balls, a chair, and a racquet. Courier sets the box on top of the chair. With a swipe of his wrist, he sends a ball to Fish's forehand. Fish rips it down the line.

"Bigger," Courier says.

Fish unloads into a cross-court forehand.

"Left shoulder down and accelerate," Courier says, feeding several balls in quick succession.

"You're like Nick Bollettieri," Fish teases, referencing the infamously hard-driving Florida tennis coach who trained a young Courier, as well as Agassi, Monica Seles, and a spate of other No. 1 players.

"I think that's a compliment, but I'm not sure," Courier says.

Fish grins. "Gimme a backhand."

Courier obliges. Fish raises his racquet so high that it's almost above his head. Then he swings through the ball with a purposeful, exaggerated awkwardness, mimicking Courier's famously idiosyncratic backhand. Courier gets the joke immediately.

"You don't have the left hand fucked up enough," Courier says.

Fish and Courier, who have known each other for years, can goof around, but the tone of the practice changes when Harrison and Isner take the court. They make for a study in contrasts: Harrison, a broad-shouldered kid who moves around the court with a swagger, and the 6-foot-9 Isner, who keeps his thin, boyish face hidden beneath his ball cap.

Both have been dubbed the Future of American Tennis, but when U.S. tennis executives talk about their top prospects on the men's side, the one they mention first is Harrison, now 20, who has the raw materials – the punishing serve and ground strokes, the fitness and stamina – to be dominant in an utterly conventional way. Not so with the now 27-year-old Isner, who comes with the shocking and hilarious advantage of his height, a factor that alters the basic geometry of play. The execs tend to describe Isner as if he's a piece of breakthrough technology, like an antimatter propulsion drive or a 300-mile-per-gallon car. "A disruptive force" is Courier's phrase. "No one's ever seen the ball coming down from that high before." But so far, Isner's opponents have been able to adjust. They run him around the court, using his body against him, wearing him down. That is what happened during the 2011 Davis Cup, when Isner met Chilean Paul Capdeville, ranked No. 165, and lost in five sets.

As Isner and Harrison work through a practice set, Courier takes a position behind Isner, praising him whenever he goes on the attack: "That's what I'm talkin' about, great rip." Isner's default strategy is to keep points as short as possible: huge serves, ambitious angles. "Big man tennis," he calls it. Courier is trying to reinforce Isner's ideal game – to give him the confidence to keep choosing aggressive shots, even if he misses. Full attack mode is his only chance against the guy he'll be playing later in the week: none other than Roger Federer.

Isner hits a deep approach and comes in to net. Harrison smokes him with a passing shot. "Keep making good choices," Courier says calmly, as Isner hangs his head and walks back to the baseline. Curry leans into my ear. "That's the problem," he says, glancing at Harrison. "If Ryan can do that, there's a good chance that Roger's going to tee up."