Before every Benfica home game, reporters head to a tiny room near one of the main entrances at the Estadio da Luz to collect their media accreditation and tickets.
On the left end of the desk, they can usually find a piece of paper with the names of the teams scouting the match that day.
That one piece of paper is enough to create a series of rumours that are turned into headlines.
The scouts were among the 41,352 fans who attended the game, scribbling notes in the hope of finding the next big thing in Portuguese football.
That cold night, their eyes were all drawn to Benfica's No. 79—a small 19-year-old, with braces on his teeth and a fuzzy haircut combed to the left.
His name is Joao Felix, and as soon as he touches the ball, you realise why he's already being courted by several of Europe's top clubs.
Some of his team-mates even call him the "€120 million boy" inside the dressing room because of his release clause.
Despite being just 19, he has managed to bring the joy back to the Estadio da Luz and place Benfica in the domestic title fight once again.
There's something special about him—and Benfica fans know it.
Like a procession, they spill out of the Alto dos Moinhos metro station and walk to the stadium every chance they get because, deep in their hearts, they're aware Felix won't be around for much longer. They have to enjoy him while they can.
That night against Boavista was one of those games that will be remembered when he is gone, with the Portuguese wonderkid being directly involved in three goals during Benfica's 5-1 win.
A Bola newspaper's headline the next morning was "Served by a genius." Record, meanwhile, called him the "new golden boy" and "a hurricane."
At his age, as some in Portugal have lately been arguing, Felix seems to be even more developed than Cristiano Ronaldo was when he was still settling into life at Manchester United after arriving from Sporting CP.
The Juventus star himself came to Lisbon in the week after the Boavista game, to watch the derby from a box at Sporting's Estadio Jose Alvalade.
Ronaldo saw his former club beaten 4-2 by Benfica and a Felix masterclass. The teenager had a goal disallowed in the first half but then scored right after that, and he also won a penalty for the fourth goal. He was named man of the match.
Former Benfica vice-president Rui Gomes da Silva even joked after the sparkling display: "Portugal's best player was at Alvalade...and it was nice of Ronaldo to have gone there to watch him play."
Felix broke into the team as a playmaker, but he has been turned into a lethal striker since head coach Bruno Lage took over on January 3. Felix has scored nine goals and produced five assists in 25 games in all competitions this season.
How can anyone stop him? Now working as a football pundit, former FC Porto and Juventus centre-back Jorge Andrade caused some fuss in the country with his suggestion.
"If I still played, I would step on him and there would be no more Joao Felix during the match. They [Benfica] would have to look for another alternative," he told RTP3 (h/t Jornal de Noticias).
Despite Andrade's controversial words, bringing Felix down has not been an easy job for opponents this season.
Devastatingly effective when running at defenders, the teen star is capable of playing in every position across the forward line. With a vast skill set that will probably only get better as he develops more, he already possesses an elegance and self-confidence with the ball comparable to the best talents in the game.
He's the latest in a long line of prospects to come out of Benfica's highly rated academy, Seixal, after Bernardo Silva, Victor Lindelof and Ederson.
"It's possible and fair to say that Felix is the Seixal graduate who has raised the highest expectations in a long time," Joao Goncalves, a pundit for BTV, the club's official television channel, tells Bleacher Report.
"About a year ago, he was still playing with the B side in the tough and difficult Portuguese second division and making a difference. It's been a sustained development, with him showing proof of his huge potential every step of the way. The natural, easy and triumphant way he's establishing himself in the senior team explains the enormous hope for his future."
Born in the city of Viseu, 290 kilometres away from Lisbon, Felix arrived at Seixal in 2015. Since then, Valter Marques, who covers Benfica for Record, has lost of track of the number of conversations he has had about the player with people involved in the academy.
He was told Felix was "a pearl who would set tongues wagging," and he was quick to see that potential himself.
"It had always been a matter of finding the right timing to unleash him and give him a proper chance to reach the top," Marques tells B/R.
"There's no doubt left whatsoever about his value. The next step is making the national team, which I believe will happen very soon. After that, it remains to be seen how far the European heavyweights will be willing to go to sign him—he will probably be featuring for a European giant next season or the season after that.
"I don't think Benfica will be able to hold him."
Felix originally started his career at Porto as an eight-year-old before packing his things and heading south to Lisbon in 2015. Back then, he was deemed too small by Porto's coaches and was not getting much playing time. At the end of his contract, he decided to abandon the Dragons and join their fierce rivals.
In order to lure him to Seixal, Benfica cited the example of Andre Gomes, who had taken a similar path and successfully broken into their first team.
Porto's loss ended up being Benfica's gain.
"I would like to pick up a wooden stick and hit on the head whomever let him go," former Porto captain Rodolfo Reis said on SIC Noticias.
One of the most respected football pundits in Portugal, Luis Cristovao believes Felix couldn't have benefited more from the move, even though his shirts still look two sizes too big for him.
"He made it to Seixal when he was already 15, after seven seasons with Porto. Due to its philosophy, Benfica's academy has been, for a while, the best one at treating Portuguese talents, opening spaces for different kinds of footballers—such as Ruben Dias, Gedson Fernandes and Felix," Cristovao, who works for Eleven Sports and Antena 1, tells B/R.
"Among those who broke into their first team, Felix appears to be, without a doubt, the one with most indicators that he will be become a great player.
"Despite still being 19, he's been very quick in showing an array of qualities that can easily take him to another level."
Almost impossible to stop with the ball on his feet, Felix seems to break records every other week in the Portuguese football.
He was promoted to Benfica's B team when he was just 16, becoming the youngest player of all time to debut and also score in the Portuguese second tier. At the end of that season, he was already featuring in the Portugal under-21 team, skipping three age groups.
Felix has not stopped since then, though, as netting twice in three derbies against Sporting in his breakout season showed.
B/R's football expert Sam Tighe first noticed Felix during Benfica's UEFA Youth League run in 2016-17, when he destroyed Real Madrid with a brace in the semi-final before losing to Red Bull Salzburg in the final.
"His ability to twist and turn in tight spaces, manipulate the ball, and his appreciation for space really stuck out to me," Tighe recalls.
"At the time, he was incredibly skinny and small, so it was difficult to project exactly how he'd take the step into senior football, but technical skills like his don't come around too often.
"He's taken Lisbon by storm. He's also showing athletic traits we don't see very often at youth level. When I see him storming up field with the ball at his feet and swinging in pinpoint balls, I shake my head a little. Is there anything he can't do?
"Felix looks set right for the very top. He's in the top echelon of teenagers and exciting youngsters, jostling for a spot alongside Vinicius Junior (Real Madrid) and Matthijs De Ligt (Ajax). He's not the 'name' they are just yet, but he soon will be."
The Benfica prodigy has been defined as a mix of Portuguese legends Rui Costa and Joao Vieira Pinto and has also, somewhat inevitably, been compared to Ronaldo.
And he can indeed be a bit of all three.
Felix is also being touted to become the leader of what is regarded as the most promising crop of youngsters to come through Portugal's youth system in a long time.
Don't believe the hype? Portugal won the UEFA Under-19 Championship in July, despite the absences of some of their brightest talents, including Felix, Gedson, Diogo Dalot, Rafael Leao and Diogo Leite.
A few months later, the under-17 side thrashed Brazil 4-0 to end up as winners of the Nike International Friendlies tournament.
The post-Ronaldo future couldn't look brighter for the Portugal national team.
You could already field the following starting XI of players aged 24 or younger: Diogo Costa (Porto); Joao Cancelo (Juventus), Ruben Dias (Benfica), Diogo Leite (Porto) and Diogo Dalot (Manchester United); Ruben Neves (Wolverhampton Wanderers), Bernardo Silva (Manchester City) and Bruno Fernandes (Sporting); Joao Felix (Benfica), Rafael Leao (Lille) and Andre Silva (Sevilla).
"There's a big group of players—all of them younger than 24—that seem to fit in the idea of a powerful generation, fighting, in terms of quality and number of options, with the best ones we ever had in Portugal," Cristovao argues.
Even among such a talented crop, Felix still stands out.
"His room for progression is enormous and, even so, he already displays the level of talent of the biggest stars. He's treading the same path as Bernardo Silva," Goncalves says.
"He has everything it takes to be the Portuguese football reference point for the next decade."
"With Ronaldo approaching the end of his career, there will possibly be only one player who can rival Felix in the coming years: Bernardo. I can't see anyone dethroning these two," Marques adds.
Get used to Joao Felix: He might not be at Benfica for much longer, but when it comes to the top level of European football, he's here to stay.
Follow Marcus on Twitter: @_marcus_alves