i reached the final as well of the champions league, in the semi final i won against the best team in the competition
he had like 6 points more than me
I think that any defensive formation should use a DMC to make your defense and midfield stronger.

he should play with 4 on the back because the opponent has ML and MR, so 3 DC's won't be enough, and i'm pretty sure his opponent will put red arrows on his ML and MR so he needs defense on the wings.


the DMC with blue arrow, will give an extra support to the 2 DC's, but will also help to counter attack

Now the reason to put 3 MC's is to get more control on the midfield. His opponent has 2 better MC's, so by playing with 3 MC's he could actually be stronger.

His opponent has only 1 DC, so the best way is to attack from the middle, and the 3 MC's will be helpful for that

I can't say that he will win, but this looks like a good formation to play with