Daniil Medvedev is a Grand Slam champion for the first time, having beaten the world number one in straight sets in New York City ©Getty Images

Novak Djokovic's quest to win all four Grand Slams in a calendar year was ended at the last hurdle by Daniil Medvedev - who through a stellar performance won the US Open final and his maiden major crown.

World number Djokovic one was irritable and seemingly not 100 per cent fit at the showpiece Arthur Ashe Stadium, going down 6-4, 6-4, 6-4.

Medvedev was taken past three sets only once en route to the final in New York City - whereas 20-time Grand Slam champion Djokovic required at least four sets in each of his last four matches - and the Russian's freshness showed.

The 25-year-old served brilliantly, regularly aggressive on second serve, and went unbroken through the opening two sets to move one away from victory.

And when Medvedev twice broke Djokovic in set three, an unlikely straight-sets victory appeared almost certain.

Nerves crept in, however, prolonging Djokovic's stay of execution.

Medvedev double faulted on championship point and followed that up with another double fault as Djokovic pulled it back it 5-3.

And the Serbian, who appeared to be trying to keep rallies short, won on his own serve to heap the pressure back on Medvedev.

The crowd being uncharacteristically in favour of Djokovic further made things challenging for Medvedev - and even brought Djokovic to tears in the closing set.

Another double fault came along when Medvedev forced two more championship points, but the Russian produced the goods at the third time of asking, with Djokovic unable to get the return over the net and handing Medvedev a first Grand Slam crown. 

Medvedev is just the second Russian man to win the US Open, after Marat Safin in 2000, and the first non-"Big Three" player to beat one of the Big Three in a Grand Slam final since Swiss Stan Wawrinka upset Djokovic in the 2016 US Open final.

The Big Three - Swiss great Roger Federer, Spain's Rafael Nadal and Djokovic - have each won a record 20 men's singles Grand Slam titles, and Djokovic squandered his chance to move clear today.

Both Nadal and Federer missed this tournament through injury.

Djokovic was also bidding to become the first player since Australia's Rod Laver in 1969 to win a men's singles calendar-year Grand Slam.

Following 18-year-old Briton Emma Raducanu's women's singles win yesterday, the US Open has a pair of first-time singles Grand Slam champions for the first time since 1990.