NEW YORK — Walking out for his first Grand Slam final at age 19, Carlos Alcaraz bumped fists with fans leaning over a railing along the path leading to the Arthur Ashe Stadium court. Moments later, after the coin toss, Alcaraz turned to sprint to the baseline for the warmup, until being beckoned back to the net by the chair umpire for the customary pre-match photos.

Alcaraz is imbued with boundless enthusiasm and energy, not to mention skill, speed, stamina and sangfroid. And now he’s a U.S. Open champion and the No. 1 player in men’s tennis.

Using his uncommon combination of moxie and maturity, Alcaraz beat Casper Ruud 6-4, 2-6, 7-6 (1), 6-3 on Sunday to earn the trophy at Flushing Meadows and become the youngest man to lead the ATP rankings.

“Well, this is something that I dreamed of since I was a kid,” said Alcaraz, whom folks of a certain age might still consider a kid. “It’s something I worked really, really hard (for). It’s tough to talk right now. A lot of emotions.”

Alcaraz already has attracted plenty of attention as someone considered the next big star in a sport dominated for decades by Rafael Nadal, Novak Djokovic and Roger Federer.

The Spaniard was serenaded by choruses of “Olé, Olé, Olé! Carlos!” that reverberated off the arena’s closed roof – and Alcaraz often motioned for the spectators to get louder. There were a couple of magical points that drew standing ovations, including one Alcaraz lost with a laser of an on-the-run forehand while ending up face-down on his belly.

He only briefly showed signs of fatigue from having to get through three consecutive five-setters to reach the title match, something no one had done in New York in 30 years.

Alcaraz went five sets against 2014 U.S. Open champion Marin Cilic in the fourth round, ending at 2:23 a.m. Tuesday; against Jannik Sinner in the quarterfinals, a 5-hour, 15-minute thriller that ended at 2:50 a.m. Friday after Alcaraz needed to save a match point; and against Frances Tiafoe in the semifinals.

“You have to give everything on court. You have to give everything you have inside. I worked really, really hard to earn it,” Alcaraz said. “It’s not time to be tired.”

This was not a stroll to the finish.

Alcaraz dropped the second set and faced a pair of set points while down 6-5 in the third. But he erased each of those opportunities for Ruud with quick-reflex, soft-hand volleys.

And with help from a series of shanked shots by a tight-looking Ruud in the ensuing tiebreaker, Alcaraz surged to the end of that set.

One break in the fourth was all it took for Alcaraz to seal the victory in the only Grand Slam final between two players seeking both a first major championship and the top spot in the ATP’s computerized rankings, which date to 1973.

The winner was guaranteed to be first in Monday’s rankings; the loser was guaranteed to be second.

“Both Carlos and I, we knew what we were playing for. We knew what was at stake,” Ruud said. “I think it’s fitting. I’m disappointed, of course, that I’m not No. 1, but No. 2 is not too bad, either.”

Ruud is a 23-year-old from Norway who is now 0-2 in Slam finals. He was the runner-up to Rafael Nadal at the French Open in June.

Much like Nadal, Ruud stood way back near the wall to return serves, but also during the course of points, much more so than Alcaraz, who attacked when he could.

Alcaraz went after Ruud’s weaker side, the backhand, and found success that way, especially while serving.

If nothing else, Ruud gets the sportsmanship award for conceding a point he knew he didn’t deserve. It came while he was trailing 4-3 in the first set; he raced forward to a short ball that bounced twice before Ruud’s racket touched it.

Play continued, and Alcaraz hesitated, then flubbed his response. But Ruud told the chair umpire what had happened, giving the point to Alcaraz, who gave his foe a thumbs-up and applauded right along with the spectators to acknowledge the move.

Alcaraz certainly seems to be a rare talent, possessing an enviable all-court game, a blend of groundstroke power with a willingness to push forward and close points with his volleying ability. He won 34 of 45 points when he went to the net.

He is a threat while serving – he delivered 14 aces at up to 128 mph on Sunday – and returning, earning 11 break points and converting three.

Make no mistake: Ruud is no slouch, either. There’s a reason he is the youngest man since Nadal to get to two major finals in one season.

But this was Alcaraz’s time to shine.

Some perspective: He is the first teenager to win the U.S. Open since Pete Sampras in 1990 and the first to triumph at any Slam since Nadal at the 2005 French Open.

That’s decent company.

Another way to understand how precocious Alcaraz is: The last man to win this tournament in his first or second appearance was Pancho Gonzalez in 1948, before pros were allowed into the field.

For context on the rankings, it is helpful to know that Novak Djokovic did not play at the U.S. Open or Australian Open this year, unable to enter those countries because is not vaccinated against COVID-19, and did not receive any ranking boost for his Wimbledon championship because no points were on offer for anyone after the All England Club banned athletes from Russia and Belarus over the invasion of Ukraine.

Regardless of the circumstances, it is significant that Alcaraz is the first male teenager at No. 1.

No one else did it. Not Nadal, not Djokovic, not Federer, not Sampras.

When one last service winner glanced off Ruud’s frame, Alcaraz dropped to his back onto the court, then rolled over onto his stomach, covering his face with his hands.

Then he went into the stands for hugs with his coach, Juan Carlos Ferrero, a former No. 1 himself who won the French Open in 2003 and reached the final of that year’s U.S. Open, and others, crying all the while.

You only get to No. 1 for the first time once. You only win a first Grand Slam title once. Many folks expect Alcaraz to be celebrating these sorts of feats for years to come.