France forward Mbappe having become the first teenager since Pele to net twice in a World Cup game has stolen the show.
Here we look back at other prodigious talents
George Best
George Best had already won a First Division title with Manchester United but the winger only became a true superstar at the age of 19 after a stunning performance against Benfica in the European Cup in 1966 that earned him the nickname 'The fifth Beatle'.
Fondly remembered as one of the greatest players the game has ever seen – despite walking away from top-flight football at 27 – it is impossible not to wonder about what might have been had alcohol not consumed the Northern Irishman's life.
"I was born with a great gift," he later mused, "and sometimes with that comes a destructive streak. Just as I wanted to outdo everyone when I played, I had to outdo everyone when we were out on the town."
Gianluigi Buffon
Gianluigi Buffon achieved instant fame across the footballing world in 1995 by producing a string of sensational saves to keep the mighty AC Milan at bay on his Parma debut, aged 17.
Over two decades on, the goalkeeping icon is still going strong and, despite having 40 in January, the Juventus captain is now seriously considering postponing his retirement for another year.
That is hardly unsurprising of course, since he once revealed in his ode to the game, "I was 12 when I turned my back on my goal. And I will keep doing it as long as my legs, my head and my heart will allow."
Johan Cruyff
Johan Cruyff is quite simply the most influential figure in football history. Nobody has ever changed the game so radically both as a player and a coach. Cruyff understood the game like no other, and from such a young age too.
He was just 17 when he broke into the Ajax team and yet, as legendary coach Vic Buckingham explained, "He showed us how to play. He was so mature. He was such a skinny little kid but he had immense stamina and he could do everything... God's gift to mankind in a football sense. That was Johan. And such a nice kid too."
Duncan Edwards
Despite the fact that he was just 21 when he died in the Munich Air Disaster in 1958, Duncan Edwards had already established himself as one of the most remarkable talents the English game had ever seen.
A defensive midfielder who was also excellent going forward, he became the youngest player in First Division history when making his Manchester United debut at 16 years and 185 days old.
Sadly, the football world would never discover just how great Edwards was going to be but former Red Devils boss Tommy Docherty claimed: "George Best was something special, as was Pelé and Maradona but, in my mind, Duncan was much better in terms of all-round ability and skill."
Eusebio
Benfica pulled off a masterstroke in signing the 18-year-old Eusebio, who had been starring for one of Sporting Lisbon's feeder clubs. Indeed, inside two years, the legendary 'Black Panther' had fired the Eagles to victory over Real Madrid in the final of the European Cup.
He underlined his awesome goalscoring prowess in helping Portugal reach the last four of the World Cup in 1966 but he proved himself an even more impressive sportsman by making a point of congratulating Manchester United goalkeeper Alex Stepney for a fine save in the European Cup final at Wembley two years later.
When he passed in 2014, Red Devils legend Bobby Charlton said, "I feel proud to have been both his opponent and his friend."
Paulo Futre
Paulo Futre made his professional debut with Sporting at just 17 but sensationally quit the club a year later due to a pay dispute and signed for rivals Porto.
The left winger, who drew early comparisons with Diego Maradona, won two league titles with the Dragons before turning in a man of the match-winning performance against Bayern Munich in the 1987 European Cup final at the tender age of 21.
He may never have hit such heights again due to injury but he remains a Portuguese footballing icon.
Patrick Kluivert
Patrick Kluivert achieved instantaneous superstar status, aged 18, by netting the winning goal for Ajax in their 1995 European Cup final clash with reigning champions AC Milan.
The Dutch striker subsequently signed for the Rossoneri and flopped at San Siro. However, he enjoyed a far more successful spell at Barcelona, with whom he won a Liga title in 1999.
Michael Laudrup
Andres Iniesta was once asked to name the best player of all time. Without a moment's hesitation, the Barcelona midfielder replied, "Michael Laudrup." The thinking man's footballer, the Dane saw passes that nobody else could.
He was always ahead of the game and, after making a name for himself with Brondby, the teenager earned a big-money move to Juventus in 1983 before starring for Denmark at the following summer's European Championship in France, during which he turned 20.
The forward never quite settled in Serie A but he proved his undoubted genius in Spain, becoming a key member of the Barcelona 'Dream Team' that won four successive Primera Division titles - and the European Cup - before moving to Real Madrid, where he promptly made it five Liga titles in a row.
Paolo Maldini
“Paolo was very young, so I tried to give him some advice," Franco Baresi explained. "But he needed very little; he was already a great player.”
Indeed, the legendary defender Paolo Maldini made his AC Milan debut in 1985 at just 16 years of age. By the time of Euro '88, the Italian left-back was not only a starter for his country, but also one quarter of arguably the finest back four ever assembled at club level.
Silverware eluded him with the Azzurri but he walked away from the game as a five-time European Cup winner and a shoo-in for any all-time XI.
Kylian Mbappe
Florian Thauvin admitted that even he and his France team-mates were taken aback by Kylian Mbappe's performance in the 4-3 last-16 win over Argentina, "At some points, I was wondering: 'Is he riding a scooter on the pitch?!'"
Mbappe was that fast, that good. He scored twice and won a penalty as Les Bleus stormed into the quarter-finals in Russia. After becoming the first teenager since Pele to net twice in a World Cup game, Mbappe was compared to Diego Maradona by Claudio Caniggia, while Jorge Valdano said he'll "define football for the next decade".
As for Mbappe himself, he remained humble as ever. "It's all flattering but let's put things in perspective: Pele was in a different category." True, but one wonders if we're about to see another very special teenager inspire his country to World Cup glory...
Diego Maradona
Diego Maradona didn't join his beloved Boca Juniors until he was 21 but, by that stage, the iconic No.10 had already earned a reputation as a once-in-a-lifetime talent, having made his Argentinos Juniors debut at just 15 and lit up the 1979 FIFA World Youth Championship.
“He was only a little kid, but he made such an impression in training, playing like one of the kids far bigger than him," Argentinos coach Franciso Cornejo explained. "He was from another planet. He was different.”
He wasn't wrong. Maradona led Argentina to victory at the 1986 World Cup in scintillating fashion before transforming unfashionable Napoli into Serie A champions to cement his status as a true legend of the game.
Stanley Matthews
Clubs were queuing up to sign Stanley Matthews after a stunning showing for England Schoolboys as a youngster. The winger eventually joined Stoke at the age of 15 and made his professional debut two years later, just over a month after his 17th birthday.
Remarkably, Matthews' career would last a mammoth 33 years, with the 'Wizard of Dribble' finally hanging up his boots at the grand old age of 50. "I grew up in an era when he was a god to those of us who aspired to play the game," legendary manager Brian Clough explained.
"He was a true gentleman and we shall never see his like again."
Lionel Messi
When the 17-year-old Lionel Messi scored his first Barcelona goal on May 1, 2005, against Albacete, few could have predicted that it would be the first of quite so many.
However, it quickly became evident that the Catalans had one of the most gifted players in history on their hands. By 21, the flea-sized Argentine had lifted his first Ballon d'Or and is now considered by many as the greatest of all time after collecting four more, as well as becoming Barca's record goalscorer.
As Javier Mascherano once said, "The rest of us are controlled by football; Leo controls the game."
Michael Owen
Like so many others, Champions League winner Karl-Heinz Riedle had never heard of Michael Owen when he joined Liverpool in 1997. The German was, thus, left dumbstruck by the striker's pace and poise.
"It's unbelievable when you see him play to realise that he's only 17," he said. "He's a great player already and in one or two years he will become a very great player." Riedle wasn't wrong.
Owen was still only 18 when he top-scored for Liverpool in the 1997-98 Premier League before becoming a global star with a sensational strike against Argentina in the second round of that summer's World Cup in France.
Owen went on to win the Ballon d'Or in 2001 and although his later years were blighted by injuries, he had already left his mark on the game.
Pele
Arguably the greatest player of all time, Pele was a virtual unknown outside of his native Brazil before the 1958 World Cup began but a superstar by the end of it.
The then 17-year-old attacker, who had started the tournament on the bench, netted the winner against Wales in the quarters, a hat-trick against France in the semis and then one of the most famous goals in history against Sweden in the final.
'The King' would win two more World Cups – and rack up over 1,000 top-flight goals – before his glittering career with the Selecao, Santos and the New York Cosmos finally drew to a close.
His legacy lives on, though. As the artist Andy Warhol said, "Pele was one of the few who contradicted my theory: instead of 15 minutes of fame, he will have 15 centuries."
Raul
"Look over there," Atletico Madrid president Jesus Gil enthused, pointing at a skinny 14-year-old kid clad in red and white. "My captain, Raul. Remember that name – he's going to be a phenomenon." And he was. Just not at Atletico.
When Gil decided to close all but two of the Rojiblancos' youth teams, numerous promising talents suddenly found themselves without a club, chief among them, Raul Gonzalez Blanco.
The prodigiously gifted striker was promptly snapped up by Atleti's city rivals Real at the age of 15, broke into the senior squad at 17 and had become the darling of the Santiago Bernabeu before he had even turned 20.
Gianni Rivera
Gianni Rivera is considered 'The Golden Boy' of Italian football - and it's easy to understand why. The slender attacking midfielder was just 15 when he was given his first professional start by hometown club Alessandria.
Then, after making a record-breaking move to AC Milan just over a year later, he became an Italian icon because of his silky skills and good looks. "He's an elegant young player with a remarkable touch," the legendary Giuseppe Meazza enthused after watching Rivera in action for the first time.
Although always doubted by some as too weak or too slow, Rivera was a wonderful passer of the ball and he would end his career having won two European Cups with Milan, a European Championship with Italy and the Ballon d'Or, in 1969.
Cristiano Ronaldo
Famously signed by Manchester United after leaving their defenders with twisted blood during a friendly in Lisbon, Cristiano Ronaldo bewitched the Old Trafford crowd with his tricks and flicks from the moment he made his debut as an 18-year-old.
Even George Best gushed, "There have been a few players described as 'the new George Best' over the years, but this is the first time it's been a compliment to me!"
The Portuguese has since developed into arguably the most effective goalscoring machine the game has ever seen, winning four Champions Leagues – one with United and three with Real Madrid – and five Ballons d'Or.
Wayne Rooney
Wayne Rooney had already netted in the Premier League for hometown club Everton but a star was truly born the moment he curled home a stunning, last-minute winner against reigning champions Arsenal just days before his 17th birthday in October 2002.
The Merseysider took Euro 2004 by storm, scoring four times, only for injury to intervene. Sven-Goran Eriksson nonetheless claimed, “I don’t remember anyone making such an impact on a tournament since Pele in the 1958 World Cup in Sweden."
Sadly, for a variety of reasons, Rooney would never dominate another major international tournament in the same way. However, he still became Manchester United's all-time record goalscorer before making an emotional return to Goodison Park last year.
Ronaldo
The striker was considered such a phenomenal talent in his native Brazil that he was taken to the 1994 World Cup despite having played only 14 league games in his debut season at Cruzeiro.
Ronaldo didn't feature in the United States but he would go on to become the tournament's record goalscorer in firing the Selecao to victory in 2002.
Miroslav Klose has since bettered that tally but, for many, Ronaldo remains the finest No.9 of all time. Indeed, even Zlatan Ibrahimovic considered him on a whole other level: "For me, he was the greatest. There was nobody like him."
Francesco Totti
The Roma legend made his debut for his hometown club at just 16 and would go on to break record after record.
The 2006 World Cup winner became Serie A's youngest captain at 22, leading the Giallorossi to an historic Scudetto in 2001, and ended his career at the age of 40 as the second-highest goalscorer in Serie A history.
Lionel Messi considers him "a phenomenon", while former team-mate John Arne Riise perhaps best summed up Totti's standing by pronouncing him, "The God of Rome!"
Europe's premier club competition will complete its 2019-20 edition with a final-eight World Cup-style tournament, held in the Portuguese capital, from August 12 to August 23.
After the four outstanding last-16 ties are completed at the scheduled home stadiums, the quarter-finals onwards will be held on neutral territory, with no fans present and, most notably, over just one-leg.
As things stand, teams will not have to quarantine either, with each club are likely to set up in their own hotel away from the public so that social distancing measures can be maintained.
Istanbul was due to host the 2020 final but will now be the venue for the 2021 showpiece, with all other scheduled hosts moving back a year.
Portugal was picked because of its location and the fact it has no teams left in the competition.
Organisers are proceeding on the basis that all matches will be played behind closed doors, with only essential personnel allowed on site.
