US Open champion Novak Djokovic is honoured to be considered among the greats of the game and has warned his rivals he has many years left in him yet.

Djokovic defeated world number two Roger Federer 6-4 5-7 6-4 6-4 to win his second title at Flushing Meadows and 10th major overall, moving the Serb to within one of Bjorn Borg on the Open era's all-time list.

Above Borg sit both Rafael Nadal and Pete Sampras on 14 grand slam triumphs while Djokovic still remains seven short of Federer's all-time best 17.

The 28-year-old, however, claimed three of the four grand slams in 2015 and has now reached 16 of the last 21 major finals.

The record is testament to Djokovic's consistency at the top of the men's game which, at his current rate, means there is a strong chance the Serb could match or even surpass Federer's total.

"We've got to double digits now," Djokovic said.

"And I'm so obviously flattered and honoured to be a part of an elite group of players, legends of our sports to manage to win this many grand slam trophies in their lives and careers.

"So to be just mentioned alongside them is truly something special."

Djokovic is one of the greatest athletes the game has ever seen, taking meticulous care of his diet and physique, and it would be no surprise if his career extended well into his thirties.

"I'm 28. I have always valued the care for my body and my mind and had this holistic approach to life," Djokovic said.

"I will continue on with the same kind of lifestyle, same kind of approach. I think that kind of approach brought me to where I am today.

"Hopefully this kind of approach will give me longevity and that I can have many more years to come and, as I said, many more opportunities to fight for these trophies.

"As long as there is this fire in me I will be coming back."

Djokovic's only grand slam defeat this year came in the French Open final to Stan Wawrinka, meaning he went one better than his famous 2011 season, when he also won the Australian Open, Wimbledon and US Open but lost in the semi-finals at Roland Garros.

The Serb has been the stand-out player in the world again this year and believes his performances have been even better than four years ago.

"I think it's definitely more difficult to repeat something like that than actually doing it for the first time," Djokovic said.

"I'm a different player, a different person today than I was in 2011.

"As a father and a husband, it's a completely different approach to tennis today.

"I feel more fulfilled. I feel more complete as a player today than I was in 2011 - physically stronger, mentally more experienced, and tougher as well.

"I think being in the situation before helped me to understand particular obstacles that are on the way and how I need to overcome them, which I did last night."

Djokovic was a worthy winner against Federer, who came into the final having not dropped a set since Wimbledon in July, but the 34-year-old could not overcome his opponent's relentless hitting and masterful defence.

The Swiss missed 19 break-point opportunities as Djokovic was more clinical in the important moments, showing his iron-will again to secure a hard-fought victory.

"To win against one of the biggest rivals, an all-time grand slam champion, somebody that always keeps fighting till the last point, keeps making you play an extra shot - all these things now are very special to me," Djokovic said.

"This is a night that I will definitely remember for a very long time."