Wawrinka, described by Djokovic as a player who rises to the big occasion like no other, admitted he was a mass of nerves before Sunday’s championship match.
“I was shaking in the locker room," he said, adding that during his last minute discussions with coach Magnus Norman “I start to cry".
“I was completely shaking," said Wawrinka, although he added that through it all he remained convinced that he had the game to win.
“Physically I was there. My game was there. Put the fight on the court, and you will have a chance to win," he told himself.
That’s exactly what Wawrinka did, shaking off the loss of the first set to post a 6-7 (1/7), 6-4, 7-5, 6-3 victory over 12-time Grand Slam champion Djokovic.
He denied Djokovic a second straight US Open title, and for the third time beat a reigning number one in a major final.
Wawrinka had already been pushed to the limit in reaching the final.
He’d spent nearly 18 hours on court, saving a match point in a five-set thriller over unheralded Briton Dan Evans in the third round.
He had to rally against former US Open finalist Kei Nishikori in the semi-finals, and escaped resurgent former champion Juan Martin del Potro in a quarter-final four-setter.
“I think this Grand Slam was the most painful, physically and mentally, that I ever played," Wawrinka said. “I was feeling tired already at the beginning of the match. I was feeling the cramp coming in the third set."
Feeling pain in the fourth, Wawrinka said he was determined “not to show anything" but just to “give everything and keep fighting and go try to win it".
Wawrinka, who had handed Djokovic two of his biggest Grand Slam disappointments, including in the French Open final last year, said he expected his marathon tournament to be capped by an endurance test against the Serb.
“There is no secret," Wawrinka said. “If you want to beat the number one player in the world you have to give everything.
“You have to accept to suffer and you have almost to enjoy to suffer."
Wawrinka said things weren’t so difficult in 2014, when he won his first Grand Slam title at the Australian Open, downing Djokovic en route to a meeting with then-number one Rafael Nadal in the final.
Back then, just reaching the final was an accomplishment to celebrate.
“I came on court to win it, but I knew it will be OK to lose it," Wawrinka said.
“But then, then, then .... I’m not that young anymore," he said. “You’re in another final of a Grand Slam, you don’t want to lose it ... because the trophy of the winner and the finalist is not the same."
Wawrinka said his late career success is not the product of any grand design, but just the culmination of years of dedication.
“First I wanted to be a professional tennis player," he said. “That means living with your passion, with your sport. Then (my goal) was to be top 100, then top 50.
“I never start anything (saying) I want to be number one, I want to win a Grand Slam. For me, it’s always step by step.
“The only thing I want to do is push the limit."