ATP World Tour No. 1 Novak Djokovic captured his 10th piece of silverware in what has been a remarkable season as he beat defending champion Rafael Nadal 6-2, 6-4, 6-7(3), 6-1 in the US Open final on Monday in New York.

Novak Djokovic and Rafa Nadal produced some astonishing tennis in the US Open final, with the Serb eventually winning in four sets.

Novak Djokovic might still be the king of tennis but it took a struggle of epic proportions over four sets at Flushing Meadows to rip Rafael Nadal’s fingers from his remaining crown.

It is the sixth time this season that Djokovic has beaten Nadal, with all of their contests coming in finals. He defeated Nadal in the finals of ATP World Tour Masters 1000 events in Indian Wells, Miami, Madrid and Rome, before dethroning the Spaniard at Wimbledon. It was the first US Open final to feature the world’s Top 2 players since 1995.

The sustained quality of the exchanges, in rallies that ran to 30 shots and more, left the 24,712 excitement junkies packed into the Arthur Ashe stadium delirious on a balmy New York Monday night and the combatants drained of the last drop of their genius.

Upon being announced as the 24th different US Open champion, Djokovic said, “It really sounds unreal; it’s an incredible feeling. I had an amazing year and it keeps going. Every time I play Rafa it’s a big challenge. I want to congratulate him on a great tournament again. I wish that we will have many more tough matches in the upcoming years. It’s an absolute pleasure to be a part of the very few players that have won this trophy throughout history.”

It took the world No 1 four hours and 10 minutes to subdue the reigning champion.

It was not just the length of the fight that made it such a compelling sporting occasion but the ability and willingness of both players to come back from impossible positions.

After victories at the Australian Open (d. Murray) and Wimbledon earlier in the year, Djokovic becomes the sixth man in the Open Era to win three Grand Slam championships in the same season. The 24-year-old Serbian captured his fourth major title overall, having also triumphed at the 2008 Australian Open.

Nadal lost his serve 11 times, yet never gave up; Djokovic, battered in the tie-break, took a medical time-out at the start of the fourth set, then immediately broke Nadal, going on to finish a job he had looked like completing maybe two hours earlier.

It is the first time that Djokovic has laid his hands on the US Open trophy, having twice before finished runner-up. In his first major final in 2007, he lost out to Federer, and he was beaten in four sets by Nadal last year as the Spaniard completed the career Grand Slam.

The tournament was introduced by an earthquake, survived a hurricane, was embarrassingly mismanaged as courts and nerves cracked in the second week as the elements returned to mock the organising committee, then was marred by a Serena Williams tantrum on Sunday. But the men’s delayed final restored the championship’s integrity in the most emphatic manner.

As he did in 2010, Djokovic reached the final at Flushing Meadows after saving two match points to defeat Federer in a five-set epic in the semi-finals. The Belgrade native rallied from two sets down for the second time in his career, and saved two match points when Federer led 5-3, 40/15 in the fifth set.

The crowd responded to the mood. Several times the chair umpire, Carlos Ramos, had to call for quiet from supporters of both players who were shouting either during serve or on critical strokes in a rally. The interruptions seemed to disturb Djokovic more than Nadal.

Djokovic has compiled a staggering 64-2 mark in 2011, including a perfect 41-0 start to the season which ended in defeat to Federer in the Roland Garros semi-finals. The Serb’s only other defeat this season came against Andy Murray in the Cincinnati final, where he retired with a shoulder injury.

The 25-year-old Nadal was bidding to win his 11th major title and second of the season after capturing a record-equalling sixth Roland Garros crown (d. Federer) in June. The left-hander has been left in the shadows by Djokovic this season, but has still compiled extremely strong results, recording a 59-11 win-loss mark and reaching nine tour-level finals (3-6 record).

It was an unequivocal statement by Djokovic. There can be no argument that he has the measure of not just Nadal but Roger Federer, the world No3 whom he beat in that remarkable semi-final on Saturday. It was his third slam title of the year, after Melbourne and Wimbledon, and only a magical reincarnation of the old Federer stopped him reaching the final at Roland Garros. Andy Murray was the other player to beat him in a year in which he hit peak after peak, culminating here with another crushing defeat of the world No2.

“Obviously I’m disappointed,” said Nadal. “This guy is doing unbelievable things, so I just want to congratulate Novak. What he did this year is probably impossible to repeat. I tried my best in every moment.

“These kind of matches are very difficult, they bring your body to the limit. I think I tried to play aggressive, but he always made a fantastic comeback. I’m happy about what I did. I ran to every ball. I fought until the last ball. This year I’ve lost a lot of finals against him. I have to accept I won a lot in the past and the only thing I can do is to try my best every day to keep improving.”

It is only the fourth Grand Slam final Nadal has lost. His three previous runner-up finishes all came at Wimbledon, losing to Federer in the 2006-2007 finals before succumbing to Djokovic as defending champion this year.

If this were a fight, Nadal would have been punched to a pulp at the end but Djokovic’s knuckles would have been bruised beyond recognition. Djokovic, who has a win-loss record in 2011 of 64-2 with more to come, hit him hard and deep, wide and handsome, then had to take similar punishment in return.

There was such ferocity in some of the winner’s ground strokes that Nadal had to reply leaning back and hitting from way behind the baseline. For sustained passages of play he simply could not get into range to hit easy winners. His points were dredged from desperate deaths or scored on his opponent’s errors.

Nadal started so well and had the majority of the crowd with him when he broke Djokovic early in each of the first two sets, only to surrender the advantage at once. Stirred, Djokovic retaliated fiercely.

But the Mallorcan’s serve let him down at crucial points, dipping to 50% in the second set, when he looked like being blown away. But nobody could doubt Nadal’s fighting heart.

On one of the few occasions when he had Djokovic on the back foot, 2-0 up at the start of the second set thanks to six unforced errors by his opponent, he was perfectly placed to extend his lead.

Then came the game of the match: a 17-minute duel on Nadal’s serve in which he was dragged into eight deuce points and Djokovic finally broke him on the sixth opportunity. It came at the end of another long, gruelling rally, Nadal, straining backwards in mid-court banging a tired smash into the net.

If that was the longest war, there were several other skirmishes nearly as tough. In the fifth game of the third set, having broken back in the previous game, a 27-shot rally at 40-30 up ended in agony for Nadal and another deuce battle. They traded so many quality shots in the exchanges that followed it seemed the game would never end. When it did, the ball flew limply down the tram-lines off Nadal’s racket to give Djokovic yet another glimmer of a kill.

The mutual respect between them is palpable and that is something not always evident at the summit of international sport. They did their sport a great service.

Novak Djokovic, born 22 May 1987,  in Belgrade, Serbia, to father Srdan and mother Dijana, and today is your best day.