Tomislav Milicevic had been watching the game for around 10 minutes when he opened his battered brown notebook and turned to the page where he had written down the two starting lineups. Using a red pencil, he put a circle around the name Luka Jovic.
Milicevic, then working as the coach of Red Star Belgrade's under-12s, was attending a youth tournament in the Bosnian city of Bijeljina, which sits just across the border from Serbia. When he set eyes on Jovic, then aged eight years old, he was transfixed.
"After 10 minutes of play, I noticed something unbelievable," Milicevic told Bleacher Report.
"The ball was glued to his foot. He was comfortable when he had the ball and he was thinking about what to do with it, whether to lay it off immediately or try to keep it. I found it amazing that a boy of his age was able to play in that way and to keep possession so skilfully."
When the ball came to Jovic in front of goal, Milicevic was even more impressed.
"He reminded me a bit of Gerd Muller, with a similar physical stature," says the 78-year-old. "Luka was good with both feet. He had a good sense for buildup play and team play, and I saw that he had an unbelievable goal instinct. You can't learn that; it was given to him by Mother Nature. And he still has that goal instinct today."
Jovic's instincts in front of goal have turned the 21-year-old striker into one of the most coveted players in European football, with a list of suitors thought to include some of the biggest clubs on the continent (Chelsea, Barcelona, Real Madrid, and Manchester City have all been linked).
Stocky and quick, in a manner that brings to mind players like Romario and Sergio Aguero, Jovic strikes the ball crisply with both feet and seems blessed with an innate sense of timing. He also has an eye for the spectacular, as demonstrated by the outrageous flying back-heel against Schalke that propelled Eintracht Frankfurt into last season's DFB-Pokal final, or the sublime mid-air volley that sparked his five-goal haul against Fortuna Dusseldorf in October.
Six goals in nine games have taken Eintracht into the knockout stages of this season's Europa League, and his 15 league goals have him vying for supremacy with Bayern Munich's Robert Lewandowski (17) at the top of the Bundesliga scoring charts. Milicevic has not been disappointed.
You could be forgiven for thinking there must be something in the water in Bijeljina. Savo Milosevic—the Serbian national team's second-highest all-time scorer—also hails from the area, and Zlatan Ibrahimovic has roots in the region via his father.
Jovic grew up with his parents and sister in the rural village of Batar, 14 miles south of Bijeljina.
His father, Milan, had played football at amateur level and encouraged Jovic to work on his shooting with both feet. Although he initially favoured his right foot, he learned to hit the ball just as confidently with his left. As a teenager, he idolised Ibrahimovic and, in particular, Radamel Falcao, once writing their names in brackets after his own on his Facebook profile.
A childhood Red Star fan, he needed little persuading to join the club's academy, but the journey 90 miles east to Belgrade presented a daily obstacle.
"It wasn't easy for him," recalls Milicevic. "In the beginning, he travelled every day by bus from Bijeljina to Belgrade and back. He made sacrifices and his family supported him.
"He grew up in a very poor home. When I saw that, I was even more convinced that he would make it."
Slavisa Stojanovic became Red Star's head coach in June 2013, and from the moment he arrived, he was told by the club's directors to keep an eye out for the tyro coming through the youth ranks.
Word of Jovic's ability had spread through Belgrade football circles, and Stojanovic regularly found himself fielding questions from local journalists about why the youngster was still waiting to make his first-team debut.
Stojanovic brought Jovic into the first-team squad in early 2014, yet the teenager's lack of application on the training pitch sometimes drove him to distraction.
"He was a very talented player. He had a nose for goal, a natural gift," Stojanovic told Bleacher Report. "But I got angry with him sometimes because he looked so lazy on the training field. At that time, he had slightly longer hair and in some training sessions he was more focused on his hairstyle than anything else."
A fondness for chocolate, crisps and doughnuts also led Red Star officials to harbour concerns about Jovic's diet. When the Red Star squad were staying together in the club's accommodation building, senior players would occasionally get a key for Jovic's room from reception so they could perform sweeps for sugary treats.
"He really liked that sort of stuff at that time," says Stojanovic with a chuckle. "The players would take it out of his room and he wouldn't be happy."
Jovic's commitments with Serbia's under-17s delayed his first-team debut for Red Star, but by the time the final match of the 2013-14 season came around, the stars had aligned. Red Star had won the Serbian title three days previously, so the squad travelled to Novi Sad for their final fixture against Vojvodina on May 28 in a relaxed frame of mind.
In the 73rd minute, with Red Star trailing 3-2, Stojanovic sent Jovic on in place of Nigerian striker Ifeanyi Onyilo.
Three minutes later, Milos Ninkovic floated a pass over the Vojvodina defence and Jovic chested the ball down before rolling a left-foot shot into the bottom-right corner to rescue a 3-3 draw. In doing so at the age of 16 years, five months and five days, he supplanted Dejan Stankovic as Red Star's youngest scorer.
"I said to him just a simple thing: 'Enjoy your football. Don't be afraid. And I know that if you get into the box, you will score,"' says Stojanovic, who is now head coach of the Latvian national team.
"It was a nice moment for me and for him. We celebrated the goal like a championship goal."
The following season, having upgraded his squad number from 40 to nine, Jovic became the youngest player to feature against Partizan in the Eternal Derby. Red Star general director Zvezdan Terzic vowed: "Jovic will become the best striker in Europe."
After two seasons as a member of the first-team squad, during which he scored a further 12 goals, Jovic joined Benfica in February 2016 in a transfer engineered to ease Red Star's crippling financial problems.
The move to the Estadio da Luz took Jovic down a path previously trodden by fellow Serbs such as Nemanja Matic, Lazar Markovic and Ljubomir Fejsa. But it would be in Lisbon, Portugal, that his career stalled.
Facing strong competition for a first-team place from Kostas Mitroglou, Raul Jimenez and Jonas, Jovic spent most of his time playing for Benfica's reserves. He made only two league appearances for the first team, both from the bench.
Even when he looked set to be given a chance to start a game, he blew it by allowing himself to be caught in a nightclub on the eve of the match, as he admitted in a May interview with Mozzart Sport.
When Jovic pitched up in Frankfurt in June 2017 on a two-year loan deal with a reported €7 million option to buy, he had made only two first-team appearances in the previous 12 months and remained uncapped at senior level.
Expectations were understandably low, but when he started to strut his stuff at Eintracht's summer training camp in the Tyrolean town of Gais in northern Italy, a frisson of excitement swept along the touchline.
"Even in the first training sessions, I thought, 'Wow, this boy is really, really good,'" says Julian Franzke, who covers Eintracht for German sports magazine Kicker.
"He barely needed a chance to score a goal. Sometimes you only need to see a player once or twice to know they have something special."
The move to Germany brought Jovic under the orders of Niko Kovac, who would have a profound effect on his career. The former Croatia midfielder, now in charge at Bayern Munich, was an unforgiving taskmaster, but his emphasis on on-pitch effort and off-pitch discipline enabled Jovic to get back on track.
The Balkan connection did not end with Kovac. Jovic was brought to the club by Eintracht sporting director Fredi Bobic, the Slovenia-born former Germany international, and joined a squad that also featured Croatia's Ante Rebic and fellow Serb Mijat Gacinovic. Another countryman, winger Filip Kostic, arrived on loan from Hamburg last summer.
Jovic was used sparingly by Kovac, notably sitting out Eintracht's 3-1 win over Bayern in the DFB-Pokal final, but since the attack-minded Adi Hutter took charge last summer, he has become an instrumental figure.
His quintuple against Fortuna—three goals with his left foot, one with his right foot, one with his head—made him the youngest player to score five goals in a Bundesliga game and only the third non-German. The shirt he wore in the game now sits in the club museum. He gave the match ball to his parents.
Since the start of November, Hutter has taken to aligning Jovic alongside Rebic and French target man Sebastien Haller in a fluid and dangerous front three. Eintracht typically line up in a 3-4-1-2 formation, with Jovic and Rebic taking it in turns to drop into the hole. Between them, the trio have scored 80 goals since the beginning of last season.
Jovic has averaged a goal every 102 minutes in the Bundesliga this season. Should he beat Lewandowski to the Torjagerkanone, the award given to the Bundesliga's leading scorer, he would be the first Serbian player to win it and only the fourth Eintracht winner after Jorn Andersen, Tony Yeboah and Alexander Meier.
"I don't know if Frankfurt have ever had a player with his qualities in the box," says Franzke. "I don't know if any fan can remember a player like him."
Jovic made his international debut against Chile in June last year and got a fleeting taste of action in the FIFA World Cup as an 89th-minute substitute in Serbia's group-stage loss to Brazil. He has been included in Mladen Krstajic's squad for Serbia's friendly against Germany and opening Euro 2020 qualifier against Portugal in late March.
In the meantime, the transfer speculation continues to mount. In words that will have given his English admirers pause, Jovic has declared he is "not a big fan of the Premier League," telling Japanese magazine World Soccer Digest: "I don't like the style of play there. I would like to continue playing in Germany, or alternatively in Spain, Italy or France."
Wherever he ends up this summer, 2019 is already destined to be a year to remember for Jovic, and not only because of his exploits on the pitch. His partner, Andjela Manitasevic, gave birth to the couple's first child, a baby boy, in Belgrade on February 23.
In time, Jovic Junior will come to learn that his dad is a very popular man. Because once people have made a note of his name, they tend not to forget it.