Spain's Carlos Alcaraz sealed his second US Open title after a four-set win over Italy's Jannik Sinner in New York.

Alcaraz broke the Sinner serve in the first game of the match, as he raced away with the first set 6-2 in a little over half an hour.

But Sinner wasn't going to take defeat lying down, and fought back to take the second set 6-3.

Much like the first set, the third part of the match saw Alcaraz dominate, with his serve, almost impregnable over the last two weeks, again firing.

The fourth set proved to be much more cagey, and Sinner had his chances, but erred when the opportunities were presented to him, as Alcaraz broke in the fifth game of what turned out to be the final set.

By beating last year's US Open champion, Alcaraz usurps the Italian as the world number one tennis player atop the ATP rankings.

How did the crowd react to the presence of Donald Trump?

Sunday's final had a delayed start, after tightened security due to the attendance of US President Donald Trump meant streams of people were held up entering the Arthur Ashe stadium.

Trump was met with boos by some sections of the crowd.

Sealed with an ace

But the players received a much warmer welcome, particularly during some epic points that defied belief.

And it was ultimately Alcaraz that took the spoils, winning the title with an ace on his third championship point.

Alcaraz's victory ends Sinner's 27-match winning run at hard-court Grand Slams.

"I tried my best today. I couldn't do more," said Sinner.

The contest between Alcaraz and Sinner marked the first time the same two players had met in three major finals in a row in a calendar year. Alcaraz won an epic final against Sinner in the French Open, saving three championship points en route to a five-set victory. Sinner exacted revenge a few weeks later, in winning the Wimbledon final against the Spaniard in four sets.

"I'm seeing you more than my family," Alcaraz joked, eliciting a grin from Sinner. "It's great to share the court, to share the locker rooms, everything."

US Open throws up statistical quirks

Sinner's loss extends the longest drought without a successful men's title defense of any Grand Slam in the Open era. 

No man has retained the US Open crown since Roger Federer won five in a row between 2004 and 2008.

On Saturday, top-seeded Aryna Sabalenka retained her US Open title with a straight-sets victory over Amanda Anisimova.

Edited by: Dmytro Hubenko