The two that preceded the Wimbledon classic were easier victories, a semi-final rout en route to the French Open title and a four-set victory in last year's U.S. Open semi-finals, when Nadal dominated the final three sets. The 19th edition of the Djokovic-Del Potro rivalry offers to be a fascinating contest.
"I don't know how it looked, but it felt really good", said Djokovic, who is aiming for a third US Open championship and 14th major title.
Then he returned to the baseline to serve again and eventually finished out the set before stopping.
Loss of motivation after winning all there was to win, personal problems away from the court and an elbow injury that required surgery were all partly to blame for the decline of the then world No 1, who lost the spot to Andy Murray in November 2016 and has not had it back since.
Novak Djokovic rates the US Open as his "most successful Grand Slam", despite amassing fewer titles in Flushing Meadows than at Wimbledon and the Australian Open.
The No. 1-seeded Nadal has a history of tendinitis in his knees and he said he felt a problem in the right one early in the first set.
Nishikori has enough about him to make this a competitive affair and we should see plenty of long rallies, but if Djokovic plays to his best then there will only be one victor. But the one thing that is agreed upon unanimously is this - no one in the era of "Big Four" deserves Grand Slam glory more than Juan Martin del Potro. "You could imagine very hard for me to say goodbye before the match finish but at some point you have to take a decision".
"It means the world to me obviously", he added.
Nadal appeared to be having trouble with his right knee and even pointed to it while explaining to Del Potro his reason for retiring.
That sense of possibility was lost to Del Potro for years as he sought in vain for a solution to painful wrist injuries.
"Because he plays so fast, he makes me more alert from the first point". They are the first pair to win Wimbledon and the U.S. Open in the same year since Jonas Bjorkman and Todd Woodbridge in 2003.
Last October in Basel he retired without entering the court, before the Spaniard went on to try his luck in London, but, after losing the first match against Belgium's David Goffin, his body said enough.
"I feel that I fight all my career against these kind of things".
Serena Williams will play for her record-tying 24th Grand Slam singles title after advancing to the U.S. Open final with a 6-3, 6-0 victory over Anastasija Sevastova. You never know what could happen in the future. "I know what is going on with the knee".
"I think I was just exhausted from last couple matches".