On Sunday, he won the gold medal in Beijing. On Monday, he boarded a plane for New York as the no. 1 tennis player in the world. On Tuesday, he soothed his jet lag with a round of golf. On Wednesday, he strolled into the National Tennis Center in Flushing, Queens, just before noon, signed a few autographs, and leisurely practiced with a young hitting partner for an hour without a coach, or anyone to retrieve stray balls, in sight. Let us reintroduce you to Rafael Nadal, the best tennis player in the world.

Roger Federer may have won this title the last four years, but Nadal is the man to beat at this year’s U.S. Open. He won’t admit it. Nadal says he still considers Federer the greatest player in history, still considers him the favorite to win his fifth consecutive U.S. Open, still considers him the favorite to regain the no. 1 ranking before the year ends. As confident as Nadal is these days, he remains unfailingly humble, perhaps the most humble no. 1 the game has ever known.

If you had been in Australia earlier this year, you might have witnessed a more telling scene about Nadal’s true character. A few hours after he lost in the semifinals to Jo-Wilfried Tsonga, Nadal walked into the players’ cafeteria, dressed in shorts and a T-shirt. The lights were low and the sun had set (he had played in the evening), and the place was mostly empty, with only two reporters killing time as they waited for an interview with Tsonga’s coach. Nadal walked up to the cash register, dangled a bag of potato chips in front of the gentleman behind the counter, and presented his tournament badge for inspection. The man behind the register swiped it and then sheepishly informed Nadal that his food allowance had been used up. Nadal had no cash, so he put down the chips, said thank you, politely refused the man’s offer for a free snack, and calmly walked back to the men’s locker room.

Imagine this story with Jimmy Connors as its main character. Instead of a befuddled counterman, we might have a dead one. Connors could be vicious on court and off; Nadal, the most imposing and intimidating man on the court today, is well-mannered and often shy. Nadal still lives with his parents in Mallorca, Spain. On Sunday evenings, he eats dinner with his grandmother. After winning on the lawns of Queen’s Club, a Wimbledon warm-up tournament, earlier this year, Nadal flew on EasyJet — known for its cheap prices and frequent flights, not its comforts — so he could play golf at home, and fish with his father, before returning to London for Wimbledon. In Beijing, he delighted in festive opening ceremonies and the atmosphere of the Olympic village as if he were a freshman in college spending his first week away from home. He was a popular freshman, too: Michael Phelps, the winner of eight gold medals, went out of his way to meet one athlete in Beijing, and it wasn’t Federer. Jamie Staff, a British cyclist, had a chance encounter with Nadal in the village laundry room.

“I didn’t bother him but he was shoving all his colors and whites in together,” Staff told the BBC. “I really wanted to say, ‘Dude, you’re going to have a nightmare with that.'”

If you had never seen Nadal play tennis, you might wonder how such a harmless person instills so much fear in his opponents. It is his peculiar talent to be both friendly in life and merciless — and supremely determined — on court. He intimidates opponents with his biceps, his high-octane warm-up routine (he bounces in front of the net like a boxer), and his tireless legs. If he shows emotion during matches, it is positive emotion: You’ll see very little whining from Nadal and only glimpses of self criticism, but more than a few fist-pumps and celebratory kicks. When a chair umpire warns Nadal for taking too much time between serves, he carries on as if the umpire does not exist. Bounce, bounce, serve, and prepare for the next point. Repeat. His powers of concentration are reminiscent of Bjorn Borg, the man who proved time and again that the mind is a more useful weapon than the forehand. In today’s game, Nadal’s mind is unmatched.

Nadal has never played well in New York. Last year, he lost in the fourth round. His best showing came in 2006, when he lost in the quarterfinals. Every year, the story has been the same: Nadal is tired, Nadal can’t cope with the fast hard courts of Flushing, Nadal can’t win with defense on a surface that rewards the game’s hardest hitters.

This year, you can discard those plotlines. Rafael Nadal, circa 2008, is not the Rafael Nadal we once knew. For the first time, the 22-year-old from Spain has the tennis world at his command. He handles power with ease and produces plenty of his own. He serves better than ever. He takes more chances yet doesn’t make more mistakes. His left-handed forehand, which produces twice as much spin, according to a recent study, as others in the sport, dips, bounces, and curves unlike any shot in the history of the game (and yes, he is naturally right-handed). In his finest moments this year — the Wimbledon final and the gold medal match in Beijing — Nadal didn’t so much hit the ball but direct it to the perfect place, manipulating it like a video game wizard might aim a digital ball on his flat screen television.

Can he do the same thing in Flushing? The summer of Nadal continues on Monday. Here’s saying he wins this major, too.

Mr. Perrotta is a senior editor at Tennis magazine. He can be reached at tperrotta@tennismagazine.com.