Peter Maes was in the gymnasium at Genk's training centre when Leon Bailey's extraordinary precocity struck him for the first time.
It was August 2015, and Bailey had just signed for Genk from Slovakian club Trencin. The Jamaican winger had recently turned 18, and Maes, who had been appointed head coach three months earlier, planned to ease him into the first-team picture.
But as Bailey told him during their first conversation in the gym inside the Jos Vaessen Talent Academy, Genk's high-specification youth training facility in northeast Belgium, the new boy was in a bit of a hurry.
"The first words that he said to me were: 'I've come to Genk, and I want to learn here, but in three years, I want to be playing in a bigger competition than the Belgian league,'" Maes told Bleacher Report. "I thought to myself: Wow. Even very talented players don't talk like this, but he has unbelievable confidence.
"I never believed that he was going to play directly [in the first team], but he had very strong belief in himself. He saw what was in the squad. He saw that he had a chance to play, and he went for it."
Bailey had spent time at Genk in his mid-teens—footage his adoptive father, Craig Butler, posted on YouTube shows him in action against Club Brugge in November 2012—but Belgium's Ministry of Labour questioned the legality of the arrangement, and Bailey had to leave, eventually winding up in Slovakia.
He quickly made up for lost time on his return. Genk was where players such as Kevin De Bruyne, Thibaut Courtois, Yannick Carrasco and Sergej Milinkovic-Savic launched their careers, and it was apparent from the start that Bailey was destined to follow a similar trajectory.
"My first impression was that he was a real quality player, a very athletic player," Maes said. "He was 18 years old, and his body was unbelievably athletic. He did everything at very high speed, which is very difficult. It was wonderful to work with a guy like him."
Lithe, left-footed and lethally quick, Bailey made his first-team debut 12 days after his 18th birthday and swiftly became a fixture in the first XI, scoring six goals in 37 Belgian Pro League appearances and being voted Belgium's Young Footballer of the Year.
His performances helped Genk to qualify for the Europa League, and the following season he scored seven goals in his first 12 matches in European competition, including a sublime first-time effort against Rapid Vienna that UEFA named the tournament's best goal.
Bailey's playing style—his direct running, his provocative dribbling, his powerful shooting—reflected the single-minded attitude he revealed in that first conversation with Maes. From time to time he would overstep the mark—such as when, having been sent off during a 6-0 defeat at Oostende in November 2016, he became involved in a foul-mouthed exchange with a Genk supporter—but Maes made allowances for his obstinate spirit.
"Making fights with coaches, making fights with supporters, making fights with guys from [other] clubs—OK, but tomorrow is another day, and he would forget things quickly," said Maes, who is now head coach at Lokeren.
"He was not easy to coach because he believes in what he's thinking, and you need very strong arguments for him to do something else than what he's thinking. But all of these things were done with respect. He is a guy with a good heart. He's very smart, and he's a survivor."
Europe's elite clubs were soon circling, prompting reports of interest from Chelsea, Liverpool and Roma, but Bailey's next destination was Bayer Leverkusen, who signed him in January 2017 for a reported fee of €13.5 million.
Given the No. 9 shirt, Bailey had to make do with substitute appearances in his first half-season at the BayArena, and although he kept a low profile on the pitch—failing to score in his first 10 outings—he made himself rather more conspicuous off it.
While visiting a gym on a trip to Genk in April 2017, Bailey mocked a boxer in a video that he posted on Snapchat (since removed), only for the angered pugilist to track the teenager down at a nearby cafe and film himself administering a humiliating dressing-down (warning: link contains NSFW language). The incident spawned disparaging headlines in Germany. Leverkusen sporting director Rudi Voller said Bailey had "made a mistake and must learn from it," per Kicker.
Bailey's long-awaited first Bundesliga start proved to be a false one—he was substituted at half-time of a 3-1 defeat at Bayern Munich on last season's opening weekend. But he made amends on his next start, setting up goals for Kevin Volland and Lucas Alario in a 3-0 home win over Hamburg. He then hit a stunning patch of form as autumn bled into winter, scoring 10 goals in 18 appearances between September and February. His opener in Leverkusen's 4-1 win at Hoffenheim in January—an outrageous back-heel from 12 yards—was a work of art.
Bailey's ability to operate on both flanks tallied well with Leverkusen coach Heiko Herrlich's flexible approach, which obliged the team to master multiple formations. Bailey finished the campaign with 12 goals and six assists in all competitions, and even though his form tailed off, sports magazine 11 Freunde named him their Best Newcomer.
This summer's transfer window brought with it the familiar swirl of transfer speculation—speculation that Bailey himself was happy to entertain, per Sky Sports—but with the new Bundesliga season's approach, Leverkusen announced last weekend he had signed a new five-year contract. The full-backs of the German top flight are not off the hook yet.
For people in his native Jamaica, watching Bailey take the Bundesliga by storm merely served as confirmation of a talent that first appeared when he was playing in local junior competitions arranged by the Kingston and St Andrew Football Association (KSAFA).
"There was a buzz about him in the local media back then, because he had a phenomenal record," Simon Preston, a sports reporter with Jamaica's RJR Gleaner Group, said.
"He averaged four goals per game at under-13 level, and no other player had done that since the inception of the competition."
Bailey's mother raised him in Kingston's tough Cassava Piece district, and he cut his teeth in street football matches with older boys before joining Butler's Phoenix All-Star Academy at age eight. Butler nicknamed him "Chippy," because of a supposed resemblance to Alvin from Alvin and the Chipmunks, and later adopted him.
Butler set Bailey's career as a professional footballer in motion when he took the youngster, as well as his biological son, Kyle, to Austria in the hope of finding them a European club.
"We didn't have any experience of winter, and we came to Europe with only one jacket," Bailey told Deutsche Welle.
"And we came during the wintertime. It was in February, when it's really cold in Austria. We were young—I was 12, turning 13. We didn't have so much money. Sometimes we'd have tuna and bread for breakfast, lunch and dinner, just to get through the day."
Over a period of years, Butler hawked the two youngsters around Europe—Austria, Belgium, the Netherlands and Slovakia—and Bailey trained with a multitude of clubs (among them Ajax, Anderlecht, Club Brugge and Standard Liege) before Genk finally took him on when he turned 18. The outspoken Butler is a divisive figure—the KSAFA banned him from football for six years after a court battle over club ownership, and Preston describes him as a "difficult character"—but he has nonetheless been the chief instigator of Bailey's career.
For now, it is a career that has been restricted to club football. Bailey has played for Jamaica's Under-23 team, scoring a free-kick in a friendly game against the Cayman Islands in March 2015, but has rejected approaches from the senior side, citing reservations about the Jamaica Football Federation, which has prompted fears in his homeland that he will end up playing for Belgium or Germany.
"Many people are concerned that Leon Bailey is going to end up marrying a German woman and eventually getting a German passport and representing the German national team," Preston said.
"But they still have optimism that he will represent Jamaica. At some point in the next few years—perhaps the next World Cup qualifying cycle—I think that he will be in the colours of Jamaica."
As he told the New York Times' Rory Smith earlier this year, Bailey considers himself "100 percent Jamaican," and although he is yet to don the yellow shirt of the Reggae Boyz, he remains highly visible in his birth country. Leverkusen's games are shown live on Caribbean cable channel Flow Sports, and Bailey appeared regularly on Jamaican screens during the World Cup in a television commercial for KFC.
Bailey is close to Manchester City's Jamaica-born forward Raheem Sterling and describes Olympic track legend Usain Bolt as a "close friend." Three seasons into his professional career, he is already one of the most high-profile Jamaicans in world sport.
And at 21, he has only just left the starting blocks.