They will win for story progress. If they lose or it ends with a tie, they're out of the tournament. To advance to the next group stage, each team needs 3 wins. Currently both teams won twice. If they tie in this match, the win will go automatically to Britain since so far in the tournament, they made more goals than BlueLock. There's a "best team advance" (more goal) rules in these cases.

imo makes sense why bllk would win here, the mindset england team has is the exact mindset Japan used to have, so isagi's ego shouldn't be shaken up too much compared to when france/hugo gaslit him