During the past decade, we as football fans have had the privilege of watching some brilliant players turn up week in and week out in matches that will live in our memories forever.
The 2010s are synonymous with the Messi-Ronaldo rivalry, the Madrid threepeat of Champions League titles, the dominance of clubs such as Bayern Munich, Juventus, and Paris Saint-Germain in their domestic leagues.
Cristiano Ronaldo is now 34 years old, and Lionel Messi is 32. The likes of Georgio Chiellini, Marcelo, Luca Modric, and David Silva are also not getting any younger. Arjen Robben recently just retired, whereas Frank Lampard and Steven Gerrard are now managing European clubs.
Although the likes of Messi and Ronaldo are not here to leave any time soon, the 2020s brings with it a whole new generation of talent. It will bring to us a whole new pool of players who are young right now but are set to take over from their idols soon.
As we are about to enter a new era of football, we take a look at five of the best U21 players in the world who will be the torchbearers for the next generation of superstars.
#5 Kai Havertz
Dubbed as the next big thing by fans in Germany, the sky is the limit for Bayer Leverkusen's Kai Havertz. At 20, Havertz is arguably the most talented German youngster heading into the next decade, having already proven his worth in the Bundesliga with Leverkusen.
Havertz is a classic playmaker - he has great technique on the ball, gets into good positions on the pitch to receive a pass, and his vision rivals that of players more experienced than him. In addition to this, he has a deadly eye for goal.
Havertz was the first teenager since Thomas Muller to score more than 15 goals in the Bundesliga, and he did it playing in midfield. There's effortlessness and an incisive edge to the youngster's game, which makes him versatile and a complete player in the middle of the park. Goals, assists, ball distribution - the 20-year-old has it all, and he looks set for success in the coming years.
Amidst strong interest from several of Europe's heavyweight clubs, it will be interesting to see where Havertz ends up. Wherever he does, that team will have a gem for the future.
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#4 Matthijs de Ligt
Matthijs de Ligt was the captain of Ajax at the age of 19 for a good reason. The Dutch international just turned 20, and yet he has the assuredness and mentality of a veteran who has seen it all. With the physique of a top defender and a skill set which is technically sound, de Ligt is one of the most talented players in his age group.
As such, it came as no surprise to anyone when Juventus spent big bucks to Ajax to acquire de Ligt's services.
Strong on the ball, de Ligt is known for his speed, strength, aerial prowess, and his overall understanding of the game which far exceeds his age. He is the youngest player to start in a European final (17 years and 285 days), and he is the first defender to win the Golden Boy award. It is indeed scary to think that this youngster is yet to even enter his peak years.
Because he is currently playing for Juventus, the pressure on de Ligt is perhaps more than the pressure on any of the other players on this list. Regardless, with his mindset and personality, combined with the fact that he has the likes of Virgil van Dijk and Giorgio Chiellini to guide him, de Ligt can have a long career as the best centre-back in the world for years to come.
#3 Trent Alexander-Arnold
Since Steven Gerrard graduated from the Liverpool academy and made a name for himself as one of the best to ever wear a Reds jersey, every youngster who comes through the Liverpool academy has the unfortunate task of being compared to their idol.
Most of them do not make it to even the first team, let alone aid their squad to reach consecutive Champions League finals. Indeed, Trent Alexander-Arnold is an anomaly.
Having turned 21 in October, Alexander-Arnold is a Champions League winner with his boyhood club, and is looking to achieve that elusive Premier League title.
Gary Lineker recently said that the youngster is like Kevin De Bruyne at right-back - referring to his amazing passing ability and the way he sees the field.
Last season, he broke the Premier League record for most assists as a defender, when he set up his teammates 12 times. He is also adept at controlling the tempo of the play, and a lot of Liverpool's attacks flow through him and fellow full-back Andy Robertson.
Blessed with pace, strength and an athletic physique, Alexander-Arnold has become a key figure in Jurgen Klopp's team. He has come up against the likes of Leroy Sane, Neymar, and Raheem Sterling and has come out with minimal scarring.
His passing range is exquisite, and even though the defensive aspect of his game needs some work, there is no doubt that the Scouser is a generational talent who can one day lead the Liverpool squad; just like his idol Gerrard did before him.
#2 Jadon Sancho
An English teenager playing at the top level with a German club - quite an unfamiliar story, isn't it? Originally a youth product of Watford, Jadon Sancho moved to the Manchester City academy at the age of 14.
Although he showed a lot of promise, the youngster grew exasperated at the lack of playing time and made a bold switch to Borussia Dortmund at the age of 17. Since then, Sancho's development has been exponential, and he has taken the Bundesliga by storm.
The 19-year-old Londoner started to make headlines almost a year ago due to his pace down the wing, and his ability to create chances for his teammates. With a deadly eye for a pass, Sancho is one of the best facilitators in his age group, and he kept racking up assist after assist last season for Dortmund.
Sancho became the youngest player in the history of the Bundesliga to score eight goals in a season; he then ended the campaign with 12 goals and 14 assists, becoming the youngest player to reach double figures in both these categories. He was subsequently named in the Bundesliga 2018-19 team of the season.
It is no secret that eventually, the Englishman will want to move back to England. With his burgeoning potential current skill set, all of England's top clubs will be wanting to land him, and it will be worth paying a fortune to get this teenager's services.
#1 Kylian Mbappe
There are some lists which have a surprise ending - but this one does not. Kylian Mbappe has already achieved the biggest trophy in football when he won the World Cup last year, and he was an integral part of the French team who accomplished this feat.
Otherwise, Mbappe has won the Golden Boy award, helped AS Monaco win a Ligue 1 title, and has already finished as the top scorer in Ligue 1 with Paris Saint-Germain alongside winning the Player of the Year Award. All this, before turning even 21.
Making his mark with Monaco, Mbappe moved to Paris Saint-Germain in 2017 for €180 million, making him the most expensive teenager of all time. The French international has already crossed the 100 goal mark in his career and has impressed in the Champions League too - having already netted 17 in the competition.
Not only is he by far the best player under the age of 21, Mbappe is one of the best in the world. Mbappe's pace, finishing, and link-up play have made him one of the deadliest forwards in the world.
It is but a guarantee that one day, Mbappe will wear the gold and white of Real Madrid, who are his dream club.
Regardless, Mbappe will be the torchbearer for the next generation of football, and his ceiling is incredibly high.
Honourable mentions -
Gianluigi Donnarumma
Vinicius Jr.
Erling Braut Håland