Japan's Kei Nishikori stunned the tennis world - and sparked off wild celebrations in his home country - when he defeated world No. 1 Novak Djokovic in his US Open semi-final match to become the first Asian man to reach a Grand Slam singles final.
Where did this young upstart, whose previous best display was a quarter-final appearance at the 2012 Australian Open, come from? As he makes a bid to create even more history with a maiden Grand Slam crown, we unearth 10 interesting facts about the 24-year-old.
1. His coach is Michael Chang, the youngest man to win a Grand Slam title
American-born Chang, who is of Chinese descent, claimed the French Open in 1989 at the age of 17 years and four months.
The 41-year-old rose to as high as No. 2 in the world rankings back in his heyday in the 1990s, having also reached the US Open final in 1996.
He started coaching Nishikori at the start of the year on a part-time basis after the duo met at a fund-raising exhibition match in Japan.
2. He is the youngest man to have beaten Djokovic
While players like Rafael Nadal and Roger Federer are prone to the odd lapse against unheralded opponents, Djokovic had never lost to a younger man in a Grand Slam match.
Until he met Nishikori.
3. He has several nicknames
One of them is Air K, despite his relatively short height of 1.78cm by professional tennis standards; Nishikori's aggressive game features a leaping forehand that is rarely seen among his Asian peers.
Another, Project 45, was christened during his early days training at Florida's elite Bollettieri academy. It refers to his goal of surpassing compatriot Shuzo Matsuoka's ranking of 46 in 1992, the highest a Japanese man has climbed in the Open era.
4. He was the youngest player in the ATP top 100
He broke into the Top 100 in 2008 at the age of 18, also winning the ATP Newcomer of the Year that same year. He was the first Asian player to be handed the accolade.
5. His short career has been plagued by injuries
Despite his undoubted potential, Nishikori has been hampered by a litany of problems which have forced him to retire from several high-profile games.
The most recent was in the 2014 Madrid Open final in May, when he was forced to drop out due to a back injury in the third set against defending champion Rafael Nadal.
6. He had unusually supportive parents
Nishikori's parents - engineer father Kiyoshi and piano teacher mum Eri - recognised the need for him move abroad in order to nurture his unique talent after he first played the sport at the age of five in his Japanese hometown of Matsue.
His father was quoted in the book Fly, Kei Nishikori!: "Japanese tennis players have not had much success because their sense of individuality is weak when compared with players from overseas."
With the help of a scholarship, Nishikori arrived in the US as a shy, awkward 14-year-old with limited English capabilities. Training at the ultra-competitive IMG Academy in Bradenton, Florida, he flourished despite a poor track record of Japanese players succeeding, eventually turning professional in 2007.
7. He is one of the most commercially viable players on the tennis circuit
According to Forbes magazine's annual rankings, Nishikori is the fifth highest-paid men's tennis player in the world behind the big four of Djokovic, Nadal, Federer and Andy Murray. He made US$11 million (S$13.8 million) from June 2013 to June 2014.
His endorsement deals include Adidas AG, Tag Heuer, Delta Airlines and Nissin cup noodles. His win over Djokovic also reportedly ballooned sales of casual clothes brand Uniqlo's line of Nishikori's signature polo shirts.
8. This time last year, he was ousted from the US Open first round
It must feel good for him to be doing the giant-killing this year, having been dumped out in a shock straight-sets exit to world No. 179 Daniel Evans.
The list of fallen foes leading up to his final appearance is an impressive one: Milos Raonic (fifth seed), Stanislas Wawrinka (third seed) and Djokovic (top seed).
9. The Japanese are going gaga over him
In a country where football and baseball are the dominant sports, his success has ignited genuine interest in tennis.
Fans on social media have declared their love for the tennis sensation, with some even vowing to name their future children after him.
10. Win or lose in the final, he will reach a career-high ranking
Currently at world No. 10 with five tournament wins (two of them coming this year) under his belt, a Grand Slam triumph over Cilic will propel him up to fifth in the rankings.
A loss will nudge him up two places to world No. 8.