“It was tough conditions, it was really hot and humid so I knew it would be tough,” two-time grand slam winner Wawrinka said. “It’s crazy to be in the final.”

In contrast to Djokovic – who had a walkover and two matches shortened when opponents retired – Wawrinka has endured an arduous path to the title match, saving a match point in a fourth-set tiebreaker of a third-round victory over Briton Dan Evans.

In addition to that epic five-setter he’s played three four-setters.

Coming into the semis he’d spent 14 hours 47 minutes on court, a figure that swelled with his three-hour, seven-minute win over Nishikori.

Nishikori, coming off his own five-set quarter-final triumph over world number two Andy Murray, seized the initiative with a near flawless first set, breaking Wawrinka for a 3-2 lead and closing it out with an ace on set point.

He broke Wawrinka again to open the second, but the Swiss was gradually beginning to find his range and broke back to level the set at 2-2.

Trailing 0-40 in the seventh game, Wawrinka was able to save five break points to hold and knotted the match at two sets apiece with a break in the 12th game.

After taking the third and breaking Nishkori at love for a 2-0 lead in the fourth, Wawrinka appeared to be on his way.

But he found himself down 0-40 in the fifth game and after the Swiss saved two break points Nishikori had it back on serve when Wawrinka fired a backhand wide.

There was little respite for Nishikori. A quick break back and a hold at love and Wawrinka was back in charge.

“He dictated play early tonight, put pressure on me and gave me no time,” said the Swiss.

“I had to wait and fight and make him uncomfortable. He got tired and I started to be more aggressive.”

Wawrinka, who shocked Djokovic in the 2015 French Open final, was looking forward to his first US Open title tilt.

“I am really excited, I want to enjoy the moment,” he said. “I have seen the final here on TV many times, watching Roger, Rafa, Novak.”

Although Djokovic holds a 19-4 record over Wawrinka, including two victories since that Roland Garros surprise last year, Wawrinka welcomed the chance to take him on again.

“To play Novak again it will be very special,” he said.

The defeat ended 26-year-old Nishikori’s hopes of improving on his runner-up finish to Marin Cilic in the 2014 final at Flushing Meadows.

Djokovic admitted he was “completely caught off guard” when Monfils, down 0-5 in the first in 15 minutes, stood lackadaisically in the court and began chipping the ball back.

The strategy paid off as Monfils reeled off three games in a row.

“If I would get to the net he would go for the passing shot and hit some impossible gets and balls. But that’s Gael,” Djokovic said.

It was Djokovic who emerged with the set, however, and as the Serbian star raced through the second Monfils’ interest again appeared to wane.

By the sixth game the 30-year-old had won just nine points, which he managed to nudge into double figures by the end of it.

Monfils, playing in only his second grand slam semi-final after making the last-four at the 2008 French Open, theatrically hobbled off the court and was jeered.

He was booed again by sections of the 20,000-strong crowd as he dropped the first game of the third set.

Monfils said his tactics were a deliberate attempt “to get inside his head”.

A more orthodox approach saw Monfils break back for 2-2 and again for 4-2 in a third set that saw Djokovic receive treatment on his left shoulder.

Although Djokovic saved one set point, and gave himself three break chances in the ninth game, Monfils was able to extend the match, marking the moment with a mighty roar to which Djokovic responded by ripping off his shirt.

“I think I should not have allowed him to come back to the match after two sets to love up and 2-love in the third,” Djokovic said.

“He started believing in himself. I think the crowd disliked his efforts towards the end of the second set. I think he felt like he needs to step it up and start to play better, which he did.”