It seems like Myeongjeong Industries is the national champion team

The final boss of the protagonist Kang Baek-ho
Crushed Jihak High in the national semifinals, sending their ace Ma Seong-ji away on a stretcher
A regular in the national quarterfinals, losing by just 1 point to Shohoku when Kang Baek-ho is missing
Scored 50 points, 22 rebounds, and 10 blocks against a matchup advantage
Since Daeyoung is a team led by a Lee Hyun-soo version of Yoon Dae-hyeop from the national tournament
They are seen as being below Haenam
I'll skip the opponent of last year's runner-up since no info was provided
It was mentioned that Kim Pan-seok would make a name for himself nationwide through his performance in the national tournament
But the chairman of Pungjeon High said he wouldn't make a name for himself if he just gets stuck in the national quarterfinals
The opponent is either a random school or Myeongjeong High
Based on the story, I believe it is Myeongjeong High