The 19-year-old is now the youngest player to top the Association of Tennis Professionals rankings after beating Norwegian Ruud in an exciting match in front of a boisterous crowd at the Billie Jean King National Tennis Center in New York.

A single break of serve was enough for Alcaraz to claim the opening set 6-4, before Ruud won four games in a row in the second set on his way to taking it 6-2.

The pair exchanged breaks before a dramatic third set went to a tiebreak which Alcaraz dominated as he claimed the third set 7-6.

In the fourth set Alcaraz broke in the sixth game following a forehand error from Ruud, with the Spaniard closing out the set 6-3 to become the youngest US Open champion since American Pete Sampras in 1990.

Alcaraz’s run to the US Open final featured three successive five-set wins, including the latest ever finish at the tournament, of 2.50am local time, in his quarter-final triumph over Italian Jannik Sinner.

It was a second Grand Slam singles final of the year for Ruud, who has been defeated in both, although the Norwegian will move to second in the men’s singles rankings following his run to the final in New York.

Speaking on court following his win Alcaraz said: "This is something I have dreamt of since I was a kid, to be number one in the world, to be a champion of a Grand Slam.

"It is something I have tried to achieve. It is really special for me."