Carlos Alcaraz became the youngest tennis player ever to take the No. 1 position among the world's top touring men, the reward for besting Casper Ruud at the U.S. Open on Sunday.
At 19, the Spaniard is also the only men's teenager to top the Pepperstone ATP Rankings, with women giving the world much younger tour leaders for decades.
Spain's Alcaraz on Sunday beat Ruud, 23, of Norway, in the U.S. Open final 6-4, 2-6, 7-6, 6-3, a well-matched battle that would have meant either player, ranked third and fifth respectively, took the No. 1 spot.
The final doubled as a changing of the guard for a men's sport dominated by Rafael Nadal and Novak Djokovic, both nearing retirement age.
After Alcaraz won a third-set tiebreaker to go up two sets to one, he owned the fourth set, pulling away to 5-3 to serve for the championship. A service ace gave him the win.
"This is something that I dreamed of since I was a kid," Alcaraz said. "To be No. 1 in the world. To be champion."
The player from the village of El Palmar on Spain's Atlantic coast said he recognized the importance of the date, 9/11, in the U.S.
"I will remember this day with all of you," he said.
Before Nadal was ousted in the fourth round by American Frances Tiafoe, the top spot was the elder Spaniard's for the taking.
Alcaraz beat Tiafoe in a marathon semifinal match, earning his shot at No. 1.
Alcaraz's ascension amid years of domination by Nadal, 36, the player with more grand slam wins than any other in the sport's history, means the teenager's doing his part, including modeling his arsenal after Nadal's, to keep Spain dominant.
It was Nadal who, in 2005, was the last men's teenager to win a grand slam title when he triumphed at the French Open. Alcaraz may have an advantage in employing a friend of Nadal's, Juan Carlos Ferrero, a former No. 1 and longtime Nadal challenger, as his coach.
Alcaraz's Nadal-like toolbox, mental coolness, muscular physicality and groundstroke balls that weigh a ton put him in Arthur Ashe Stadium on Sunday and put his name on the Open's Tiffany & Co. champion's trophy.
"Today was a special day, evening, for both Carlos and I," Ruud said after the match. "It’s fun that both finalists will be No. 2 and No. 1 in the world. No. 2 is not too bad."
Organizers said Sunday that had the tournament set an attendance record of 888,044, many of them repeat visitors, during the three-week event in the New York City borough of Queens.
President Michael J. McNulty III of the U.S. Tennis Association said, "This will be remembered as our most spectacular U.S. Open."
"We’ve ushered in the next generation of champions," he said.