NXGN: Greenwood, Rodrygo, Saka y las mejores promesas de 2020

THEN: After stunning Barcelona with his decision to leave La Masia in the summer of 2019, 16-year-old midfielder Simons was beginning to impress for PSG's Under-19s side.

NOW: Having made the bench on a number of occasions, Simons made his first-team debut in February and has been a regular in the match-day squad under Mauricio Pochettino.

THEN: The first player born in the 21st century to score in La Liga, Gil was spending the second half of the 2019-20 season on loan at Leganes in a bid to gain experience at senior level.

NOW: Gil was again loaned out in the summer of 2020, this time to Eibar, and has put in a number of eye-catching performances for the Liga strugglers, with Barcelona reportedly now keen to bring the winger to Camp Nou this summer.

THEN: Having been at La Masia since 2012, there were fears that Konrad could be set to leave Barcelona amid interest in the United States Under-20 international from the Bundesliga.

NOW: The winger signed a new deal with the Catalan outfit, and made his first-team debut in November's Champions League win over Dynamo Kiev. Also now a full U.S. international and remains a regular in Ronald Koeman's match-day squads at Camp Nou.

THEN: The first Real Sociedad player to skip the club's 'B' team and go straight into the first-team since Antoine Griezmann, diminutive winger Barrenetxea had already found the net against Real Madrid in his short senior career.

NOW: Nineteen-year-old Barrenetxea has flitted in and out of La Real's starting XI in 2020-21 but signed a new six-year deal with his boyhood club in February.

THEN: The young midfielder already knew he would be leaving Las Palmas for Barcelona at the end of the season, with the Blaugrana having paid an initial €5m (£4.3m/$5.5m) to sign a player likened to Andres Iniesta.

NOW: The breakout star of the 2020-21 Liga season, the 18-year-old has wasted no time in making himself at home at Camp Nou, even striking up an excellent rapport with club captain Lionel Messi. Indeed, it has even been suggested that Pedri's emergence may help convince the Argentine to stay at Barca beyond the summer.

THEN: The former La Masia star was beginning to earn regular game time under Pep Guardiola at the Etihad Stadium, with City believing they had a defensive gem on their hands.

NOW: Garcia has slipped down the pecking order after informing City that he would not be renewing his contract and now looks set for a return to Barcelona this summer on a free transfer.

THEN: After becoming Ajax's youngest-ever player in September 2018, Gravenberch was a regular in Erik ten Hag's side at the age of 17, and being compared to Paul Pogba.

NOW: Gravenberch continues to get better with more experience, and his performances this season have led to calls for him to make the Netherlands squad for this summer's European Championship.

THEN: Forced to leave Barcelona in 2016 following their FIFA-imposed transfer ban, Kubo had returned to Spain in the summer of 2019 with Madrid having broken countless J-League records in his homeland. Was spending his first season in La Liga impressing on loan at Mallorca.

NOW: Kubo's loan moves this season have not gone as well. He saw his time at Villarreal ended after just six months, and he has not been at his best so far for Getafe, whom he joined in January.

THEN: One of Europe's best teenage creative midfielders, Ihattaren could be found regularly pulling the strings for PSV.

NOW: Call-ups to the full Netherlands squad followed, but Ihattaren's time at PSV could now be coming to an end following a number of disputes with manager Roger Schmidt over the course of the 2020-21 campaign.

THEN: After winning the Golden Ball at the 2019 Under-20 World Cup as an 18-year-old, South Korea international Lee was earning regular starts for Valencia.

NOW: Following a fire sale at the end of the 2019-20 season, Lee has become a key figure in Los Che's rebuild, with the club hierarchy keen for him to begin leading from the front on the pitch.

THEN: Plucked from the fourth tier of Brazilian football in the summer of 2019, Martinelli had made a superb start to life at Arsenal, becoming the first teenager to reach double figures for goals in a single season for the club since Nicolas Anelka in 1998-99.

NOW: A knee injury saw the 19-year-old miss almost the entire first half of the 2020-21 campaign, and Martinelli has struggled to force his way back into Mikel Arteta's plans since the turn of the year.

THEN: Camavinga became an overnight star in August 2019 after a highlights clip went viral of the then-16-year-old putting in a dominant performance against Paris Saint-Germain. The midfielder was soon linked with a host of top European clubs, most notably Real Madrid, as he continued to shine in Ligue 1.

FAR: Though he has suffered a minor dip in form in recent weeks, Camavinga remains one of the very best teenage talents anywhere in the world and became France's youngest goalscorer in over a century a month after making his senior international debut.

THEN: The latest teenager to swap Brazil for the Bernabeu, Madrid paid €35m (£29m/$39m) in January 2020 to sign the Flamengo playmaker, who had been likened to Kaka in South America.

NOW: Reinier joined Borussia Dortmund on a two-year loan ahead of the 2020-21 campaign, but almost saw the deal ended after six months because of his inability to make any kind of impact in the Bundesliga. Returns to Spain were mooted, but the 19-year-old has shown improved form in recent months, and scored his first senior goal in European football in February.

THEN: Having been spoken about in hushed tones around Manchester United's Carrington training base for much of his youth career, the two-footed forward was beginning to find his feet in the Premier League and had already become the clubs' youngest-ever goalscorer in European competition.

NOW: Greenwood enjoyed a superb end to the 2019-20 campaign, with his form earning him a first England cap in September. Though he has not always maintained that level of performance this season, he remains a key member of Ole Gunnar Solskjaer's attacking unit at Old Trafford.

THEN: Having beaten Real Madrid to the signing of Fati, Barcelona took the almost unheard of decision to promote the forward to the club's first-team squad in the summer of 2019 despite him having never played for the club's 'B' team. He rewarded them by breaking countless goalscoring records, including becoming the youngest ever player to find the net in the Champions League in December of the same year.

NOW: Though Fati's form dipped towards the end of the 2019-20 campaign, he was back to his best at the start of the current season, with his performances earning him a first Spain call-up. Within a month, he was La Roja's youngest-ever goalscorer, and only a knee injury suffered in November has stopped the 18-year-old from breaking yet more records.

THEN: Having made his Santos debut at the age of 16 in 2017, Rodrygo joined Madrid 18 months later in a deal worth €45m (£40m/$50m). He marked his Blancos debut with a goal after 93 seconds before scoring a perfect hat-trick on his first Champions League start. In addition, he had already been capped twice by Brazil.

NOW: Though Rodrygo has been unable to maintain his fine early goal record at Santiago Bernabeu, he remains one of the best young attacking talents in Spanish football, with Zinedine Zidane having shown over the past year that he is not afraid to throw the 20-year-old into huge La Liga and Champions League fixtures.