NEW YORK — World No. 1 Jannik Sinner arrived in New York just over two weeks ago, facing a flurry of questions and criticism after being told he had been cleared and avoided suspension after testing positive for a banned substance twice in March.

His expectations for the US Open were “low,” he said at the start.

But he leaves as a champion, leaving little doubt about his status as the best hardcourt player in 2024.

Sinner, a 23-year-old from Italy, won the US Open on Sunday with a dominant 6-3, 6-4, 7-5 performance against American Taylor Fritz before a lively, largely celebrity-studded Arthur Ashe Stadium crowd that was largely against him. Chants of “USA” and cheers of “Let’s go, Taylor” rang out throughout, but Sinner remained unfazed. He didn’t drop a point on his first serve in the final two sets of the match.

“He was too good,” said the 12th-seeded Fritz during the trophy presentation on the court. He later called Sinner “the best player in the world at the moment.”

After winning his first major title at the Australian Open in January, Sinner became the third man — and the first since Guillermo Vilas in 1977 — to win his first two Grand Slam trophies in the same season. He is also the second Italian player to win a singles title at the US Open, after 2015 women’s champion Flavia Pennetta.

For Sinner, the victory marked an emotional end to a challenging few months. The world learned on August 20 that he had tested positive for a trace of clostebol, a banned anabolic steroid, twice in an eight-day period at the Indian Wells tournament, but was acquitted after his use was ruled accidental. His defense was that the steroid entered his system via a massage from a team member he later fired.

“(It) was difficult because the conditions leading up to the tournament were not easy,” Sinner said Sunday. “I felt like I was growing match by match and my confidence was growing … I’m happy with how I handled it. I’m just happy to have this trophy with me.”

Sinner was asked about the doping case and what happened after during the tournament. Several players questioned the fairness of the ruling and wondered if he had received special treatment because of his number 1 position.

Sinner called the situation a “mistake” and insisted he was innocent and had gone through the “same process” as everyone else.

Despite the news, Sinner was largely warmly received by the New York crowd during his run. Even during the finale, dozens of Italian flags were spotted in the crowd and his highlights were met with loud ovations.

After struggling in the opening set of his first match against American Mackenzie McDonald, Sinner showed little weakness for the rest of the match, dropping just one more set — against 2021 US Open champion Daniil Medvedev in the quarterfinals — en route to the title.

Fritz, a 26-year-old Californian making his first major tournament final, opened with an early 3-2 lead, but Sinner responded by winning the next four games to take control of the set and the match.

In the third set, with the score tied at 3-3, Fritz showed signs of life with an overhead winner in the seventh game for a 15-30 lead on Sinner’s serve. He shouted “Let’s go!” to the delight of the crowd, most of whom rose to their feet in appreciation. Fritz eventually secured the break and took the next game on his serve for a 5-3 lead.

But he couldn’t close out the set. Sinner rattled off the next four games almost clinically — each point making the crowd quieter — to secure the win.

When it was over, Sinner raised his arms above his head and closed his eyes as he tilted his head back. Those in his box jumped to their feet as Darren Cahill, one of his coaches, slumped in his chair and wiped away tears.

“This title means a lot to me,” Sinner told the crowd as he accepted the trophy from André Agassi, “because the last period of my career was really not easy.”

“I feel like the fans, American fans, have wanted a male champion for a long time, and… I’m pretty upset with how I played. I feel like, I don’t know, I feel like I almost let a lot of people down.”

Taylor Fritz

Sinner said during his post-match press conference that he complimented his team and family for keeping him focused despite everything that was happening off the field.

“What made it possible for me was always the people who are close to me on a daily basis, people who have known me since I was very young, and also my family and my team and everyone who supports me on a daily basis,” Sinner said. “I always try to stay with them, especially when the moments are difficult and tough, because I know that they can help me in those moments.”

Sinner is the fourth different man to win both the Australian Open and US Open in the same year since 1988, when the Australian major moved from grass to hard courts. With Aryna Sabalenka having won both the Australian Open and US Open, it is the first time the same man and woman have won both hard-court majors in the same year since 1988 (Mats Wilander and Steffi Graf did that year).

It also marked a turning point in the men’s game, as Sinner and Carlos Alcaraz, 21, combined to win all four major titles of the year. It is the first season since 2002 that no member of the “Big Three” — Novak Djokovic, Rafael Nadal and Roger Federer — has won a Grand Slam.

Sunday was a devastating result for Fritz, who was looking to end a 21-year drought of major singles titles by American men. Andy Roddick’s victory at the 2003 U.S. Open was the last time an American man won a Grand Slam, and Fritz was the first American man to reach a major final since Roddick finished runner-up at Wimbledon in 2009.

“There are a lot of positives of course, and when I have some time to cool down, I’ll be happy that I made it to the final,” Fritz said. “But right now I’m pretty disappointed with a lot of things on the court, how I played, how I hit certain shots. It sucks.

“And I’m not saying it would have made a difference. I don’t know if it would have, but I just wanted to play better and give myself a better chance. It’s really disappointing right now. … I feel like the fans, American fans, have wanted a male champion for a long time, and … I’m pretty upset with how I played. I feel like, I don’t know, I feel like I almost let a lot of people down.”

Despite the heartbreaking final, Fritz still had a breakthrough year, becoming the first American to reach three major quarterfinals in a single season since Roddick (2007) and the first to reach the second week of all four Grand Slam events since Agassi in 2003.

Thanks to his path to the championship fight, Fritz returns to the top 10 of the rankings, at position 7.

Sinner now has a 4,105-point lead over new No. 2 Alexander Zverev. Djokovic, the 2023 champion at Flushing Meadows who was surprised in the third round, drops to No. 4 behind Alcaraz.

ESPN Research and The Associated Press contributed to this report.