I just noticed my rival just intentionally lost another league match with a even more weird formation.
Luckily, league ranking was not affected by this controlled match result. The winning team ranked 9th and do not have chance to promote before or after the match. However, the beneficiary team of previous controlled match I mentioned before was finally ranked 6th in this league. It successfully robbed a position to promote.
BTW, my rival just unfriended one of my team again to avoid to draw with it in same league next season. He will request friendship again on Day 3.