Fifteen-year-old Takefusa Kubo trained with the Japanese Under-19 squad Wednesday as the team, which consists of members expected to form the core of the 2020 Tokyo Olympics side, prepared for their two training matches away at Argentina.

Playmaker Kubo returned to Japan in 2015 after four years with Barcelona — when the Catalan club was penalized by soccer's world governing body FIFA for violating international transfer regulations — but has already been fast-tracked to the U-23 side at his new club FC Tokyo and played in a J3 match on Nov. 5.

"I'll try not to waste the chance I'm given," Kubo said after taking part in a small-sided game in Chiba Prefecture.

Coach Atushi Uchiyama in October summoned Kubo for the U-19 Asian Championship which Japan won to book its berth in the U-20 World Cup next year. The two matches against Argentina's U-19 team next Monday and Wednesday are set to provide the coach further opportunities to scrutinize players.

"I called him up because I believe he is capable of playing among this generation," Uchiyama said of Kubo.

Daisuke Sakai, captain of the U-19 side, was pleasantly surprised by Kubo's confident attitude on the pitch despite being surrounded by players who are a lot older.

"He's modest off the field but is imposing during training," Sakai said, revealing that his younger teammate actively asked for the ball during the training session.

Kubo said, "I don't believe I'm at the same level (as those in the U-19 generation). I'd like to put in more effort."