Novak Djokovic, the 20-year-old Serb with the thick black hair, winning smile, and flowing game, will have his day atop the tennis world, but for now, there’s room for only Roger Federer.

The world no. 1 and three-time defending champion survived two shaky sets, including seven set points, and captured his fourth straight U.S. Open title yesterday, defeating Djokovic 7–6(4), 7–6(2), 6–4.

Four titles in a row: It’s a feat that this tournament’s finest Open era champions — Pete Sampras, Jimmy Connors, Ivan Lendl, and John McEnroe — could not achieve. The last man to win four straight U.S. Championships, as the tournament was called then, was Bill Tilden, who won six from 1920 to 1925.

The victory also moved Federer into second place on the all-time list of major champions, tied with Roy Emerson at 12 titles and two behind Pete Sampras’s 14. The 26-year-old Federer has now reached 10 straight Grand Slam finals, a record. If he plays anywhere near his best, and has anywhere near the amount of good fortune he’s had in the last five years in terms of health, he’ll shatter Sampras’ record and seal his place as the best player in the history of the sport.

“I thought I played well when I had to,” Federer said. “I’ve played better matches in the past, no doubt.”

Luckily, he faced a young opponent who played a very young match. Djokovic is a supreme talent and he showed few signs of nerves as he climbed the rankings to no. 3 in the world, but in his first major final, he pulled punches when he should have thrown them, and swung too hard when a more measured swing was in order. He hit too many drop shots and lost control of his backhand, his steadiest stroke, during tense moments.

Djokovic’s nerves were not surprising. To play your first major final inside the loud and windy Arthur Ashe Stadium, at age 20, is difficult enough. To do it against a man who had not lost a match here since 2003, well, that’s something else entirely. The real surprise was that Djokovic had no jitters when the match began. He held his service games easily and won more rallies than Federer, and it wasn’t long before he found himself on the brink of the first set when he served at 6–5, 40–0.

At that point one could see Djokovic fighting to transform himself from a contender into a champion. He wasn’t up to the task. His backhand, solid and always a threat for a down-the-line winner, went awry — you could see him clutching his handle and shortening his swing. He made three atrocious backhand errors, yet still managed to earn two more set points. He couldn’t convert.

He couldn’t calm his nerves in the tiebreaker, either. He played Federer to 3–3 despite missing two easy backhands, but double faulted to give Federer the lead, and then double faulted on set point. He broke early in the second set and took a 4-1 lead, gave the lead back, and then put Federer in a 15–40 deficit at 5–6. Federer fired an ace, and then Djokovic missed a forehand winner by a centimeter. Federer, his serve gathering force, hit a service winner and made his first four serves of the tiebreaker for a 5–2 lead. He smacked a backhand passing shot down the line on set point.

Djokovic, to his credit, did not fold in the third set. But on match point, he dumped a drop shot into the net, his last of several foolish attempts to catch Federer off guard.

Djokovic took the loss rather well.

“My next book is going to be called ‘Seven Set Points,'” he said.

Asked how it was that Maria Sharapova and Robert De Niro were seated in his box, the quickwitted Djokovic smiled and said Sharapova was just a friend. He said he met De Niro “randomly on the street, I was sitting in a bar, he was coming up, smoking a cigarette.”

This is the third time Federer has won three majors in a year, yet this was the first year since he became no. 1 that he looked vulnerable outside the clay court season. At the Australian Open, he played marvelously and no one could touch him. But from March to July, he endured three uncharacteristic losses and parted company with Tony Roche, his coach of two plus years.

At the French Open, he failed again. Worse still, he nearly relinquished his Wimbledon crown as he tried to match Bjorn Borg’s record of five consecutive titles at the All England Club. Rafael Nadal outplayed Federer that day, but the defending champion steered clear of what might have been a crushing upset with 24 aces and dozens of service winners.

The Wimbledon escape remains the best final of Federer’s career, and it seemed to buoy him for the rest of the summer. He began the U.S. Open in top form, and he needed his best earlier than anyone had thought he would. John Isner gave the world no. 1 a fright by stealing the first set of their third-round match, and Feliciano Lopez did the same a round later. In the much anticipated quarterfinal match against Andy Roddick, Federer put on an extraordinary show, turning away the charged up American in three sets and at one point stunning him, and the crowd, by transforming a 140 mph serve into a line drive that scorched Roddick’s toes.

People often speak of Federer’s timing, how he reduces the complicated task of hitting a moving ball to the simplest, smoothest motion. Perfect timing on the court — that we all know about. But his timing is perfect off the court, too. Federer hasn’t missed a major since the 1999 U.S. Open, when he was 18 years old. He precisely plans his schedule, trains hard, and he doesn’t waste energy during matches. He’s so efficient, and so complete, that for the last four years the rest of the field has looked, for the most part, inadequate. Though Nadal and Djokovic are closer to Federer than anyone has ever been, Federer still has them beat.

“No. 2, no. 3, doesn’t matter much,” he said. “It’s no. 1 that matters.”

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