NEW YORK — It is among the most unexpected championship matchups in Grand Slam tennis history: Kei Nishikori against Marin Cilic in the U.S. Open final.

Neither is ranked in the top 10.

Neither has played in a major final, let alone won one.

“If somebody told you ‘a Nishikori-Cilic final at the U.S. Open,’ three weeks ago, you would look at them like they don’t know what they’re talking about,” said 2001 Wimbledon champion Goran Ivanisevic, Cilic’s coach. “But it’s happening on Monday.”

Yes, it is, putting an end to a 38-Slam stretch in which at least one — and 17 times, two — of Roger Federer, Novak Djokovic and Rafael Nadal participated in the title match, winning 34 of them.

Cilic eliminated Federer 6-3, 6-4, 6-4 in the semifinals. Nishikori, a star in his native Japan but based since age 14 in Florida, got past Djokovic 6-4, 1-6, 7-6 (4), 6-3 to become the first man from Asia to get to a major singles final. (Nadal, the 2013 U.S. Open champion, did not try to defend his title because of a right wrist injury.)

“Well,” Cilic summed up, “it’s a bit of a changeup.”

And just think about where these two guys were a year ago at this time.

Cilic was at home in Croatia, barred from entering the U.S. Open because of a doping suspension he says he didn’t deserve. He tested positive for a stimulant at a tournament in Germany in May 2013, and the International Tennis Federation sought a two-year ban. He said he ingested the substance unintentionally via a glucose tablet bought at a pharmacy.

He initially was suspended for nine months, but the Court of Arbitration for Sport reduced that to four on appeal last October, saying, “the sanction imposed was too severe.” The court also restored ranking points and prize money.

“You can see there’s justice,” Ivanisevic said. “There’s somebody upstairs watching. He was accused for nothing. He was sitting ... for nothing.”

Nishikori left Flushing Meadows 12 months ago with a straight-set, first-round loss to a qualifier ranked 179th. He arrived this year with a reputation for injury issues. As recently as three weeks ago, he was forced to hit shots while seated at practice, because he couldn’t run after having a cyst removed from the bottom of his right foot in August.

“I tried to work on my body a lot this year,” said Nishikori, who has won five of seven previous matches against Cilic. “Even last year, too.”

And now? Nishikori is viewed in a different light after winning a pair of five-setters against No. 3 seed Stan Wawrinka and No. 5 Milos Raonic before beating No. 1 Djokovic in stifling heat and humidity.

“After every match that he wins,” said Nishikori’s coach, 1989 French Open champion Michael Chang, “I keep telling him, ‘We’re not done yet.’ ”

Nishikori is seeded 10th but ranked 11th. Cilic is seeded 14th but ranked 16th.

It’s the first time since the 2002 French Open that two men outside the top 10 have met in a Grand Slam final. That hasn’t happened in New York since Patrick Rafter beat Greg Rusedski in 1997, which also was the last year two players made their major final debut at Flushing Meadows.

“It’s going to be a tricky final,” Ivanisevic said. “But whoever wins is going to be on top of the world. You know, Mount Everest is Monday.”