As the top league competitions throughout Europe get under way, some of the focus will be on a group of talented youngsters – all of whom are not yet 21.
Some, including Paris Saint-Germain’s Kylian Mbappé and AC Milan’s Gianluigi Donnarumma, are already household names, while others, such as Erling Braut Håland and Kevin Danso, are not widely known outside their own clubs.
Mbappé is already a World Cup winner, having won it with the Les Bleus in Russia last year.
He scored four goals, including one in the 4-2 victory against Croatia in the final.
Like Mbappé, Donnarumma has experience that belies his age.
In 2015, he played his first Serie A match as a 16-year-old. A year later, he became the youngest goalkeeper to play for the Italian senior team when he came on as a substitute for Gianluigi Buffon.
He has since played 164 Serie A matches, conceding 166 goals and keeping 59 clean sheets. He has played 12 matches for Italy.
Another senior international is Borussia Dortmund’s Jadon Sancho, who played his first game for England last year as an 18-year-old when he came on against Croatia in the World Cup.
Sancho played youth football for Watford and Manchester City, but left the Citizens in 2017 for Borussia Dortmund in the Bundesliga for £8 million (R144 million).
That fee, however, pales in comparison to what Atlético Madrid paid for Portuguese forward João Félix (19). The Spanish club sold World Cup winner Antoine Griezmann to Barcelona for £107.5 million in June, but then paid Benfica £142 million for Félix.
The youngster is said to be on his way to becoming the next Cristiano Ronaldo.
But Félix has remained grounded: “Ronaldo won five Golden Balls, it’s every player’s dream. Of course I’d like to be like him.”
Under-21 players who are already household names and some who have shown it's possible to excaell
However, Atlético coach Diego Simeone has been quick to shut that discussion down.
“No, I don’t think João Félix is like Cristiano. The reality is that he has a good game to observe. I’ve enjoyed watching him since he arrived.
“He has vision and good control going forward, which speaks well for his age, and how he plays and how he reads the game,” the Argentine coach said.
Håland and Danso are also on the verge of making names for themselves in Europe.
Danso is one of several England-trained youngsters who has found a home in the Bundesliga, while Håland grabbed his share of headlines earlier this year during the Under-20 World Cup – nine goals will do that for a player.
The Norwegian, whose father, Alf-Inge Håland, was a team-mate of Lucas Radebe at Leeds United in England, scored nine goals in his country’s 13-0 victory against Honduras at the Under-20 World Cup.
There are, of course, a host of other players younger than 21 who will feature for some of the top clubs in the leagues this season.
These include Vinicius Junior (Real Madrid/Brazil), Trent Alexander-Arnold (Liverpool/England), Matthijs de Ligt (Juventus/Netherlands), Callum Hudson-Odoi (Chelsea/England), Diego Lainez (Real Betis/Mexico), Christian Pulisic (Chelsea/US) and Nicolo Zaniolo (Roma/Italy).
But for the likes of Félix, Erling Braut Håland and dozens of others who have been tipped for stardom, there are plenty of examples that the path to glory is paved with obstacles.
Ghanaian striker Nii Lamptey debuted for Anderlecht as a 16-year-old and was described as the “next Pelé”.
But, as rapidly as his star rose, it fell as he became a journeyman footballer, playing for small clubs in Italy, Argentina, Turkey, Portugal, Germany, China and Dubai, before finally hanging up his boots after an unsuccessful stint with Jomo Cosmos in 2008.
The next “next Pelé” was another Ghana-born player in Freddy Adu, who was signed by MLS side DC United as a 14-year-old, becoming the youngest player to score in the MLS in the same year. Aged 16, he became the youngest player to play for the US senior side.
Like Lamptey, his career then took a nosedive and he has played for 14 clubs in eight different countries. At the end of last year, he was released by USL Championship team Las Vegas Lights and is currently coaching youngsters.
However, the 30-year-old still dreams of making it big again.
“I’m still plenty young. I’m not ready to give it up. Things haven’t gone the way that I would have wanted them to, obviously. But I love the sport too much to say I’m ready to give it up.”