Who is the child who finally appeared in Our Youth to challenge Wu Tong?

Joule said that he didn't know the elementary school brother. Du Tang was seen by all baseball players and learned from them. Because Joule is a school trumpet, he should have met everyone in the school. So it's probably a new actor.

Also, I don't know if you remember. Xiaosong Ban called a person before the first episode of the match. This man seems to be faking illness (a stomachache). Maybe it was him?