The 31-year-old defeated Juan Martin del Potro 6-3, 7-6 (7-4), 6-3 in the US Open final to claim a third success at Flushing Meadows and make it back-to-back major titles.
This was Djokovic's third championship in NY, along with those in 2011 and 2015.
A focused Djokovic continued to apply pressure in the third set until Del Potro finally cracked on serve to fall behind 5-3, with the Serb closing out the match with a ferocious overhead victor.
However, the odds were stacked against the 29-year-old journeyman took on the sixth seed Djokovic for a spot in the semi-finals on Thursday. One game alone in the second set lasted 20 minutes.
"1-2-3;-Osaka-at-No. -7-after-US-Open-title">rightfully back atop the rankings for the first time in 3½ years, with Nadal at No. 1, Federer at No. 2 and, as of Monday, Djokovic at No. 3. Nadal, Federer and Djokovic last occupied the top three spots in the rankings in April 2015. He now trails Roger Federer's record of 20 by six and is just three behind Rafael Nadal for second all-time.
The Serb, who was back in the final for an eighth time and contesting his 23rd Grand Slam final - the third most in men's tennis history - was serving exceptionally well and earned a break in the eighth game after showing tremendous patience before successfully serving out the set.
He said: "If you told me in February this year when I got the surgery that I'd win Wimbledon, the US Open and Cincinnati then it would be hard to believe".
'I don't know the answer.
Del Potro backed Djokovic to surpass Federer's mark of 20 Slams.
In one charge at the net, Djokovic picked a del Potro volley off his toes and sent back a victor.
Federer and Nadal have made me the player I am today.
For quite some time after that Djokovic looked towards Del Potro's singing friend with utmost anger, unable to get them out of his head and that showed on the court.
"I was so close to desired level, and then I just completely underplayed that match". He was earmarked as the next big force, the man alongside Djokovic to rattle the two great champions he had just felled to break through.
When Djokovic is in peak health, as he finally is following a long bout with a right elbow injury that eventually required surgery after this year's Australian Open, he is most definitely a man on a mission.
Despite defeat, world number three Del Potro remained proud after an achievement he never thought would have been possible during his injury hell.
In the tiebreak, Del Potro looked susceptible to forehand errors and Djokovic showed enormous courage and quality to take it away from Del Potro, going up 2-0 in the final.
You are only a first-time major singles champion once, of course.
While Simona Halep of Romania retained her top spot on the list, Germany?s Angelique Kerber moved one spot up to acquire the third position.
When it ended, thanks to a three-game closing run by Djokovic, he flung his racket away and landed on his back, arms and legs spread wide.