It will be the first time since the Australian Open final in 2005 that a men's grand slam final will not feature at least one of tennis's top three - Novak Djokovic, Rafa Nadal and Roger Federer.
Tenth seed Nishikori is the first Asian man to reach a grand slam singles final, while Cilic is into his first final, less than 12 months after returning from a four-month suspension for what he said was inadvertently taking a banned supplement.
Before this year's US Open, Nishikori and Cilic boasted just one grand slam semi-final appearance between them, the Croat having made it to the last four at the Australian Open in 2010.
Nishikori leads their head-to-head meetings 5-2, including both their meetings this year, in Brisbane and Barcelona, while they split their two previous US Open clashes.
But having beaten Djokovic and Federer respectively to reach their first grand slam final, they will be desperate to take chances on Monday.
"I hope there will be a lot of people watching (in Japan)," said Nishikori, who also beat third seed Stan Wawrinka and fifth seed Milos Raonic.
"I am a little bit surprised to make the final but am very happy to make another (piece) of history, the first time an Asian man is in the final. I hope I can win and make (more) history."
Coached by former grand slam champion Michael Chang, Nishikori has added steel and physical strength to a game that always possessed flair but lacked endurance.
"He's been really helpful," Nishikori said. "He's been helping me a lot from the end of last year, (especially) mentally.
"I feel my tennis is changing (to be a) little more aggressive and playing with more confidence. He's tough, but I needed someone to push me."
Cilic, whose victory over Federer in the semi-finals was described by his coach, Goran Ivanisevic, as "perfection", is aiming for glory, 11 months after returning from a drugs ban that left him questioning his future.
Originally banned for nine months, Cilic's suspension was cut to four months on appeal and the 25-year-old always maintained that he had taken the banned substance without knowing, through a tainted supplement.
The road back to the top was hard but with the help of former Wimbledon champion Ivanisevic, he has emerged a more aggressive player, using his serve and groundstrokes to stunning effect.
"For the guys that are top, (reaching the final) feels normal," he said. "But for some guys that are making it for the first time it's the achievement of their career.
"When I'm playing now these bigger matches I feel like if I'm going to play well I have a good chance.
"That's a different mind-set than I used to have because before I felt that I should (try to do) more than I'm able to and then your game breaks."
Cilic said he was looking forward to one more great battle with Nishikori.
"It's going to be a special day for both of us, an opportunity for both of us to win a grand slam, to be a part of history," he said.
"There are going to be definitely huge emotions on the court. We have different game styles. I think it's going to be a good tactical match-up."
