Twelve months ago, the swashbuckling Spaniard, who will be playing in his 18th grand slam final, sat at home in Manacor, nursing his troublesome knees and fearing his career may be finished at just 26.
But after seven months out of the sport, Nadal has been a revelation.
He has won nine titles, including a record eighth French Open, taking his major haul to 12, stacked up a 59-3 victory run as well as a perfect stretch of 21 wins on hard courts.
"With no doubt he's the best player this year, no question," said Djokovic on Saturday.
Nadal leads Australian Open champion Djokovic 21-15 in a career rivalry that began at Roland Garros in 2006.
Their 37th meeting will be a record for head-to-head meetings, beating the 36 duels that John McEnroe and Ivan Lendl fought in their careers.
Nadal, 27, has won five of the past six meetings, a stretch that started after Djokovic won their epic 2012 Australian Open final, played over a gruelling five hours and 53 minutes - a record for a grand slam final.
One of Nadal's wins was in a pulsating French Open semi-final in June where Djokovic led 4-2 in the final set before Nadal hit back to keep the Serb still waiting for a maiden title in Paris, the title he needs to complete a career Grand Slam.
Both men will be chasing their second US Open title in New York - Djokovic was champion in 2011, beating the Spaniard the year after Nadal completed his career Grand Slam by seeing off the Serbian in four sets.
Despite his mastery over the Serb, Nadal said he would have been happier to see someone else on the other side of the net today.
"I prefer to play against another one, but it is what it is," said Nadal. "I want to play against a player where I have more chances to win.
"But I played against him a lot of times. Always we played very exciting matches.
"When you are involved in these kinds of matches, you feel special. Even if I lost that final in Australia, I feel happy to be involved in that match."
Nadal beat Richard Gasquet, the French No8 seed, in straight sets in Saturday's semi-final and he referred to his injury problems when he said: "It's just amazing. After what happened last year, to have the chance to play in the final is a dream for me."
Djokovic, 26, is playing in a fourth successive US Open final, fifth in total and 12th major championship of his career.
He made the final by edging Stanislas Wawrinka in a five-set semi-final in what was his 14th consecutive run to the last four at a grand slam, stretching back to the French Open in 2010.
It is also his third major final of the season after seeing off Andy Murray, who was the defending champion in New York, in Australia before being overwhelmed by the Briton at Wimbledon.
Djokovic is already guaranteed to retain the world No1 spot today and he is buoyed by having won the pair's past three grand slam finals played on faster courts - Wimbledon and the US Open in 2011 and the 2012 Australian Open final.
"Facing Nadal is the biggest challenge that you can have in our sport," he said. "He's the ultimate competitor. He's fighting for every ball and he's playing probably his best tennis ever on hard courts.
"He has got injuries, many injuries on this surface, but now he looks fit. But I have played him already here twice in the finals. I know what I need to do."
Nadal also has an extra incentive to win today - to rescue bruised Spanish pride at Madrid's failure to win the right to host the 2020 Olympics.
"It's very hard and tiring for all of us, because the country and the city of Madrid worked a lot to have the chance so many times," said the 27-year-old Mallorcan.
"We feel that we deserve it.
"I was disappointed because we felt that we were in a good position."