Darkness falls as Rafael Nadal finishes his practice session in the California desert town of Indian Wells. He's sitting courtside surrounded by his coach, his physio, and his practice partner when the opponent he'll face later tonight, David Nalbandian, heads onto the same court, followed by his coach, his physio, and his practice partner. Physically, the players are opposites: Nadal's golden-umber skin, deep-set inky eyes, and prominent cheekbones evoke 19th-century paintings of Mayan chiefs; Nalbandian's blond ponytail, long stubble, and messianic blue eyes recall a pirate on an extended binge.

Nalbandian saunters over to Nadal, his insistent machismo lending the meeting of the two camps the air of the Jets confronting the Sharks, but with high fives all around. Nadal is friendly and polite, but he's subdued, probably because of his history with Nalbandian, who is known as King David in his native Argentina and is a strike-first player who can beat anybody when he's in the mood, which he isn't in all that much.

Still, in the past two years, Nalbandian is the only man to have developed a winning record over Nadal, the number one-ranked player in the world. Nalbandian has beaten the Spaniard convincingly in the two matches they've played. In this third encounter, in March at the BNP Paribas Open, Nadal has a lot at stake. If he loses, it means there's an opponent out there who's got him figured out.

In the locker room Nadal goes through his standard pre-match drill. He showers, gets his ankles taped, gets taped below his knees. He ties on his Nike headband, puts on headphones, and listens to Spanish pop and The Phantom of the Opera while jogging around and jumping in place.

Shortly after 11 pm he enters the arena, emerging apparition-like through the benign haze of desert heat. The court is his domain, the realm he commands, but tonight the intimidation factor belongs to Nalbandian. Nadal plays defensively, allowing Nalbandian to capture the first set. Late in the second set, the pro-Nadal crowd sinks into mute apprehension when Nadal butchers a service game and gives Nalbandian a match point. Nadal fends it off, then fends off three more as fans erupt with fervid cries of "Vamos Rafa!" When Nadal snuffs out a fifth match point with a ferocious backhand winner, the crowd goes wild, which is saying something when you're playing in a retirement community and it's one o'clock in the morning.

Revived and aggressive, Nadal seizes the second set. By now Nalbandian has tried everything and made the mistake that Nadal forces you to make: He has tried too hard. Like a matador vexing a bull, Nadal bedevils his opponent, crushing any lingering hopes he harbors of escaping unscathed. At last, Nadal moves in for the kill, purposeful, pitiless, imperturbable.

"I change completely," Nadal will say later. "I decided to change."Even now, even after Rafael Nadal has established himself as the best player in tennis and one of the fiercest competitors in sports, there are those who dismiss him as "one big arm" and regard his unseating of Roger Federer, the man who held the number one spot for four and a half years, as the sports equivalent of a wrecking ball shattering Michelangelo's David. Here's what's wrong with that equation: It assumes that Nadal's game is a blunt instrument, an exercise in brute force, unrelenting attrition, and nothing more. It ignores his elemental brilliance: the lethal cross-court backhand, the thrilling retrievals crafted by lunging forehands, the clearheadedness of his shot selection on critical points.

Yet of the many advantages Nadal holds over opponents, the most significant isn't his speed or his heavy, lefty shots; it's that he's impossible to prepare for because of the unbelievable topspin he puts on balls. His true edge is his "ackitude" – a.k.a. "attitude" in non-Rafa English. It's a mentality that's grounded, unflinchingly realistic, and reflexively wise.

Some call it poise, but it's more than that. Nadal has a rare gift for living in the moment, and the rarer gift of being able to produce precisely what that moment requires. This was evident during his match with Nalbandian, when he demonstrated that his greatest strengths include the intangibles that don't show up on the stat sheet: his relish for battle, his ability to take his own measure, his force of will. And it was evident after he beat Federer in the final of the 2009 Australian Open, a contest that unequivocally established Nadal as the sport's crown prince, rather than its overachieving pretender.

During the trophy presentation, Federer cracked. "God," he blurted while addressing the crowd, "it's killing me."

Nadal raised his trophy with reluctance, out of respect. He was solemn as he turned to Federer. "Remember, you are a great champion," he told him. "You are one of the best of history."There are many things to like about Nadal, among them that he bites his newly acquired trophies rather than kissing them, that he never throws his racket in anger, and that, when his shirt gets so sweat-soaked that he needs to change it during a match, he does so sitting down, ignoring the ensuing wolf whistles instead of abetting them. These particulars may seem insignificant, and would be, if they didn't reflect the larger truth that he is not, and never has been, your classic spoiled, narcissistic athlete.

He's largely immune to the familiar seductions of fame and coddling because he wants it that way. Set to turn 23 this month, he still lives with his family on the isle of Mallorca, where he relaxes by fishing with high school friends, where his mother still admonishes him to clean up his room, and where he's dated the same hometown girl since he was 19.

At 6'1, Nadal looks strikingly taller and more slender than he does on television, with wide shoulders and a long, tapering torso. Though he has more muscle mass and power than any other player, his aspect is light, like a big convivial kid who borrowed his father's body for a special occasion. Eating, talking, watching golf, he drums his fingers on tabletops while his legs bob up and down, dispensing energy like a Catherine wheel shooting off sparks. In conversation he maintains eye contact, smiles a lot, and laughs easily, usually at himself.

One evening, in the players lounge, I play some table tennis against Nadal. As he bats the ball to me and misses some shots, I entertain the bizarre possibility that I might play better than he does. Then he quickens the pace, and I start missing, though whenever I manage to knock one by him he says, "Good! Good!"

He'd planned to play with his practice partner Marc Lopez, so after sending a few balls into the net, I set the paddle down. "Can't stop on a bad shot," Nadal insists, so we play until I eke out a good one. Then I watch as he and Lopez slap mad winners off the table, and my delusion is crushed as Nadal hunkers down, looking to win, shouting, "Come on!" in a pitch-perfect imitation of Lleyton Hewitt.

Early in his career Nadal described himself as a "simple boy." Now he's a simple young man, or, as revealed when we played table tennis, he is two simple men. There's the gentle, nurturing kid and the fierce, unyielding contender. What's noteworthy is that he's so gentle and so fierce that it's hard to square, even by those who know him best. Before a recent match, he lunched with his part-time coach Francisco Roig. They watched golf on television, joked, and laughed until Nadal headed to the locker room. Roig knew that when he joined him there half an hour later, Nadal would have undergone a metamorphosis. "He will be playing the match half an hour before it begins," said Roig, and his otherwise sunny countenance will be reconfigured into the fearsome snarl that causes Nadal's mother to remark that she doesn't recognize her son when he's playing.

Yet even when he's at his most ferocious, the core of his being is calm. He insists that he isn't calm by nature, which is no news to anyone who saw him play in his teens, when his volcanic emotions manifested in windmill fist pumps, flying leaps, and a penchant for celebrating a 15-love score as if he'd won a grand slam.

"He had to learn to keep calm," says his manager Carlos Costa, "to stay calm for the important moments, which, when he was a kid, was every moment."

It's a lesson that sustained him when he was the world's number two player for an unprecedented three years, waiting for an opening to become number one. Last year, as he neared that opportunity, rain halted the decisive fifth set of his Wimbledon final with Roger Federer. For the next hour Nadal was sequestered in the locker room with his coach and his trainer.

"Be calm," he told them. "I am going to win."The world Rafael Nadal emerged from is a man's world – an old-world man's world at that – in which a man is the head of his family and family matters above all else. As a child of that world, Nadal drew from the men who have surrounded him since birth. There is his father Sebastian, whose profound love for his only son compels him to caution, when necessary, "You are not doing the right thing."

There is his uncle Miguel Angel, known as the Beast of Barcelona when he was a defender for three World Cup soccer teams for Spain. Miguel Angel is as close to an idol as Rafael ever had and the person from whom he inherited his athletic ability and a template for handling fame with grace. And there is his Uncle Toni, his coach, a rigorous and charming moralist and former professional tennis player who taught Nadal the game and how to survive it.

It was Toni who gave him his first racket, when he was three, who was the first to recognize his nephew's champion-worthy intensity and who, upon seeing the right-handed Nadal hit two-handed ground strokes, made him more dangerous by converting him into a left-handed player. It was Toni who taught Nadal to handle adverse conditions by practicing on bum courts with bum balls, who insisted that he never throw a racket and that he unlace his tennis shoes and not yank them off, even after he was getting his gear free from sponsors. "I know it doesn't cost nothing for you," Toni told him, "but it is different for other people."

When Nadal was 14 the Spanish tennis federation invited him to train in Barcelona, the center of tennis in Spain. His parents didn't want him to go. "They were worried about my education suffering too much," Nadal says. "My uncles both agreed, so I stayed at home."

Remaining with his family would ground him, both in tennis and in life. In 2001, at the age of 15, he joined the men's tour, bringing to it the outrageous topspin generated by his prodigious strength and monstrous, arcing strokes. (Balls coming off Federer's racket rotate 2,500 times per minute; Agassi's whirled at 1,800 rpm. Rafa's 3,200-rpm shots drop precipitously, then bounce head-high before you can blink.) Two years later he made it into the top 50. If he missed out on other things, he didn't notice. He was obsessed with the game. The only thing that mattered more to him, he would say, was the health and happiness of his family.

All along, his Uncle Toni set the tone for his progress. He insisted that his nephew learn his own lessons, as when he decided not to dissuade the 17-year-old Nadal from downing three chocolate croissants before a match. "When he is playing bad because of this," Toni explains, "then he knows for next time."

The morning after Nadal won his first grand slam, at 19, at the 2005 French Open, Costa, himself a former top 10 player, encountered Toni reading a handwritten list in the hotel dining room.

"What is that?" asked Costa.

"I was thinking," said Toni, "about all the things he did bad."

"Maybe you don't tell him this today," said Costa.

"No," said Toni. "Has to be now."Tennis is a mental game, and everyone who plays it has an inner narrative that serves as a self-fulfilling prophecy or as a self-created stumbling block.

Roger Federer's narrative is one of perfection, an enviable story line provided you're winning. But when you're losing, perfection is an albatross – a "monster," as Federer puts it – because it doesn't permit even the most cursory failure.

Nadal's narrative, squarely focused on the need to improve and to strive, is more forgiving and humane. "To improve you have to have mistakes," Nadal says, "That is the problem with improving. You have to accept that problem."

He grew up on clay courts, as Spanish players do, so his game naturally assumed the clay courter's tendencies, which, as he says, include "playing hard from the baseline." But the men's game is played largely on hard courts, and is, as

tennis writer Andrew Burton notes, "increasingly about the ability to defend the corners." On hard courts Nadal was still getting pushed too far behind that baseline, ceding valuable real estate, forfeiting much of his ability to discern angles.

A few years ago, at the U.S. Open, when Nadal began overhauling his then-deficient net game, he rushed the net, smacked the ball into it, then shot an anguished look at Uncle Toni, who smiled and applauded. The point was, Nadal was heading in the right direction. He was trying. If he tried, he'd succeed. Maybe not now, but later.

In early 2008, I watched Nadal practice for two weeks and noted how assiduously he was reconfiguring his game: working on his serve, hitting flat, taking the ball early and on the rise. Playing with his practice partner, he was downright demonic, and you could see that he could beat anybody if he played that way during matches. But he couldn't. Under pressure he still returned, as players do, to what's familiar. Yet by year's end all that work yielded him the Olympic gold medal and the number one ranking.

When it's all about improving, even a loss is a potential gain. When it's all about striving, you never give up. "What Rafael transmits to other players," says coach Francisco Roig, "is, Okay, you can beat me, but I'm going to be there every minute."

"No other grand slam champion has improved like Nadal has," says tennis writer Asad Raza. "He's gone from retriever to counterpuncher to attacker. It's one of the more remarkable transformations of his game."

Yet Nadal's progress has had setbacks, and he was severely tested in 2004, when he suffered the first of two injuries, shortly after cracking the top 50. A stress fracture to his left ankle took him out of play for three months; home in Mallorca he spent seven hours a day in rehab. Costa visited him often. "He was always happy," Costa recalls, "because he's a happy guy. But he would ask, 'Do you think it will be easy for me when I get back?'"

That May, Costa took Nadal to the French Open to show him the courts and grounds. They went to a match, where Nadal lasted 10 minutes. "When you can't play," says Costa, "it's too painful to watch."

A year later, in 2005, Nadal won the French Open. But that October he endured a mysterious foot injury, and this time the road back was more arduous. "Some moments were really tough," he says. "We could not find a solution. There was no light at the end of the tunnel."

His father devoted himself to his son's recovery. In May 2006, Nadal returned to the French Open, played bold, slashing tennis, and defeated Federer in the final. Afterward, spent, he collapsed into his father's arms, saying, "Thank you, Popi."

Once there was a Roger Federer, there had to be a Rafael Nadal, if only to give the absurdly gifted Federer a chance to overcome something besides himself. Imagine how stunned Federer must have been during their initial encounter at the Miami Masters in 2004. He was 22 then, evolving into the game's most feared and majestic player. Nadal was a 17-year-old kid with a prematurely determined look, remnants of baby fat, and a tendency to fist pump anytime he hit a winner. Until then Nadal's association with the Mighty Fed extended to watching him make mincemeat of other players on television, which filled Nadal with what he calls "special motivation."

Nadal beat Federer in 70 minutes. Later, Federer remarked that Nadal "will become the most powerful left-hander in tennis," a left-handed compliment if ever there was one.

When Nadal was a kid, he didn't dream of being number one. He dreamed of winning the championship on the grass courts of Wimbledon. It meant everything to him, for himself and for Spain, a nation of clay courters that had produced only one Wimbledon champion, Manuel Santana, who won the title 20 years before Nadal was born.

Nadal made his ambition plain in 2006 by renting a cottage near the grounds rather than booking a hotel room on a nightly basis, the custom of clay courters who enter Wimbledon assuming they're three sets from leaving town. That year Nadal reached the final, taking a set from Federer, a respectable result in everyone's eyes but his own. The next year, 2007, he reached the final again. He held four break points in the deciding set, but Federer refused to lose. It was said that he wept for an hour afterward, sitting in the shower, water tumbling around him. In fact he wept much more. That night his father and Costa heard him "crying like an animal," as Costa puts it, in his small room, where the closet held the tuxedo he would have worn to the Champions Dinner, had he won the match.

Yet even then Federer felt his one and only rival encroaching. "He's a fantastic player," he said of Nadal after the 2007 Wimbledon final, "so I'm happy with every [win] I get now, before he takes them all."

The next year, 2008, he reaches the finals again. In the fourth-set tiebreaker he is just two points from the crown when he double faults, nets an easy backhand, then squanders two match points. They're titanic blunders.

Awaiting that decisive fifth set, he sits courtside, eating a banana, gulping Evian from a plastic bottle. "Time," the referee calls.

Nadal heads onto the grass court. He crouches, coiled and ready for Federer's serve. "I am far away from the title," he tells himself. "But, at the same time, never going to be this close again."

He plays on, doing what few players manage to do, which is to simultaneously settle down and rev up.

After a rain delay the match ends in semi-darkness. Moments later, Rafael Nadal strides back onto the court, the Spanish flag draped around his shoulders. He is, at last, the Wimbledon champion.To win big is to have more to lose, which is why Nadal has much at stake this spring and summer as he tries to maintain his supremacy over Federer at the French Open and then at Wimbledon, where they may write another chapter in what has become the most captivating rivalry in sports.

Has Nadal passed Federer for good? It's not that cut-and-dried, but "Nadal is 22, Fed is 27, and usually 22 to 26 are your peak years," says tennis analyst, coach, and former player Brad Gilbert. "So Fed is coming out of his peak years, and Nadal is heading into his."

What makes Nadal so dangerous, says Gilbert, who dubs him the "new Borg," is that he already plays "fantastic offense and amazing defense" and is still getting better. "What he does so well is he adjusts on faster courts. He's not resting on his laurels."

Nadal is poised, potentially, to achieve the near-impossible: a calendar grand slam. "What becomes hard is the cumulative weight of the tennis year," says tennis writer Joel Drucker, "the weight of the pressure, of factors ranging from schedule to weather to injuries to a sizzling-hot opponent. All those things play into it. If he does it, it would be one of the most incredible feats in sports history."

How does Nadal see his chances? He answers by holding his thumb and forefinger half an inch apart. "Really small," he says.

Still, he'll be out there trying, and working to get even better. What we'll be watching is something richer, grander, and more encompassing than an athlete reaching for the peak of his powers. "You can talk about Rafael's tennis, his forehand, his speed," says Toni -Nadal. "But his mental strength, his playing well when he has to battle – to me, that is most important. That's just his character."