2 teenage soccer stars who once played together as children could soon become the sport's biggest rivals since Lionel Messi and Cristiano Ronaldo

Getty/Etsuo Hara

Ansu Fati and Takefusa Kubo once played together as kids at Barcelona.

• Two of the world's most talented teenager soccer players, who once played together at FC Barcelona as youngsters, look set to become the sport's biggest rivals since Lionel Messi and Cristiano Ronaldo.
• Ansu Fati and Takefusa Kubo went seperate ways in 2015 but are set to meet again with Fati still at Barcelona, and Kubo on-loan at RCD Mallorca from Real Madrid.
• Here's how they rose to become two of the planet's most heralded youngsters below.
• Read more of our soccer stories here.
• Visit Business Insider's homepage for more stories.

Lionel Messi and Cristiano Ronaldo have gifted the world with the most intense and wonderful sporting rivalry for 15 years now.

The two superstars have matched each other in almost every sense, whether it be goals, trophies, or individual accolades - separating the pair has proven impossible.

However as they approach the twilights of their careers, it's nearing the time to pass their respective torches on. A new rivalry is emerging, one which involves two teenagers at Real Madrid and FC Barcelona, and one which began six seasons ago …

… in Tokyo on August 30, 2013. 

This was when FC Barcelona's Under-12 team had just swept Liverpool aside 5-0 at the Ajinomoto Stadium in the final of the Junior Soccer World Challenge.

The Barca youngsters, all part of the club's hallowed youth academy, "La Masia", walk proudly to collect their medals and lift the inaugural trophy.

Amongst that line-up of gleaming faces were the tournament's top scorer - a towering young striker born in Guinea Bissau - and a slight, but skillful, Japanese playmaker, who had been the main provider of goals for his African peer. 

The former was Anssumane "Ansu" Fati. The latter was Takefusa Kubo. 

The pair, now in their late teens, have since been separated. While Fati remains with Barcelona, Kubo is with Real Madrid. 

But while apart, the duo, now considered amongst the finest teenage talents in world soccer, still have their destinies intertwined - just not as team mates. As rivals. 

Born on home soil - made in Spain 

Ansu Fati was born in Bissau, Guinea Bissau's capital city, but moved to Spain with his parents at the age of just six after his older brother, Braima, signed for Sevilla FC.  

It didn't take long for young Ansu to follow in his sibling's footsteps, joining the same academy just two years later, before moving onto Barcelona shortly after in 2012, aged ten.

Getty/Koji Watanabe

Kubo and Fati celebrate together with their teammates after winning the Junior Soccer World Challenge in 2013.

Like Fati, Kubo also progressed from his home country to the heralded fields of the Camp Nou from an early age.

Kubo grew up playing for FC Persimmon in his birth town of Kawasaki, Japan, but started attending Barcelona Soccer Camps in 2009, aged eight. He quickly made a name for himself and was officially snapped up by the La Liga giant in 2011.

Having both arrived at La Masia at the same time, Fati and Kubo quickly developed a strong relationship on the field, scoring an unbelievable 130 goals between them during their first season together, according to FourFourTwo.

Next season, the pair's symbiosis continued, helping their side top its division. 

All good things must come to an end, however 

While Fati remained at La Masia, Kubo was forced out of Barcelona in 2015, after the club was found to be in breach of FIFA's newly implemented rule on signing international players under the age of 18. 

Now ineligible, by no fault of his own, to play for the Spanish giant, Kubo made his way back home to Japan to sign for FC Tokyo.

"In the end of my stage in Barça I had a bad time," Kubo told reporters at a press conference earlier this year, according to FCBN.

"Although I could not play, I had to go to see the games, and saw my mates playing and winning, but I could not be totally happy. So when I went back to Japan and could go back to play, I really felt very happy."

Read more: Jadon Sancho, a 19-year-old who has been compared to Neymar, is now worth far more than the declining Paris Saint-Germain super forward

Moving back home proved to be good move for Kubo, as he received the game time and freedom to fully establish himself as the continent's brightest young talent.

In April 2017, he scored his first professional goal for FC Tokyo aged 15 years and 10 months, hitting the winner in a 1-0 victory over Cerezo Osaka Under-23s. He was promoted to the club's first team six months later, and over the next two seasons made 18 appearances in the Japanese top flight, scoring five goals and registering four assists, according to Transfermarkt.

Getty

Ansu Fati and Takefusa Kubo in action for Barcelona and Real Madrid.

While Kubo was making a name for himself in Japan, Fati was finding himself frustrated at Barcelona. The Bissau-Guinean had to sit out from the 2014-2015 and 2015-2016 seasons thanks for the same ban which forced Kubo to leave, as well as injuries to both his tibia and fibula, says FourFourTwo.

Fortunately however, Fati had shown more than enough promise in his early days at the club to warrant his stay in Spain, and the club's faith was repaid over the following three seasons as he continued to shine for Barça's Juvenil B and Juvenil A sides - the latter for whom he finished as top scorer last year.

A reunion long in the making 

Kubo's form in Japan earned him a move back to Europe in June 2019, this time with Real Madrid, who brought him back to Spain ahead of Barcelona, reports AS. 

After impressing in preseason for Madrid, he joined RCD Mallorca on a season-long loan, where he's already established himself as a regular starter in Vicente Moreno's side, making four appearances and grabbing one assist.

Read more: Cristiano Ronaldo once dreamed of being the world's best soccer player. Now, Joao Felix wants to follow in his footsteps, according to the teenager's former club

Fati too, perhaps more noticeably, has become a Barcelona regular.

After making his first team debut against Real Betis last month, he scored his first goal just six days later, thumping home a fine header in a 2-2 draw with CA Osasuna, in turn becoming the club's youngest ever goalscorer.

He added his second goal just two minutes into Barcelona's next game versus Valencia, whilst also producing an assist for Dutchman Frenkie de Jong. 

Both player's career beginnings have seen them have plenty of praise heaped upon their young shoulders, including comparisons to FIFA world player of the year, Lionel Messi.

Barcelona themselves appeared to hail Fati the heir to Messi's throne at the Camp Nou, commenting on Instagram beneath a photo of the pair: "The present and the future."

Kubo's comparison to the 32-year-old has been more direct however, with the youngster having been affectionately nicknamed "The Japanese Messi" for his likeness to the Barcelona icon by fans and journalists across the world. 

Read more: Dani Alves says a 19-year-old Brazilian is the most talented young soccer player in the world, and his latest wonder goal for Real Madrid proves why

But while both have been compared to Messi in terms of their playing styles, their divulging paths with Barcelona and Real Madrid mean it is unlikely both can assume the role of the the majestic Argentine in their newly aired La Liga screenplay.

Instead, one, most likely Kubo considering his allegiance to Madrid, will instead play the role of Cristiano Ronaldo - Messi's long term and most fierce rival.

Once friends, now prospective enemies - the tale of Takefusa Kubo and Ansu Fati has only just begun, but it's one that could develop into the most engrossing stories of the modern era.