Wish ya luck with the match @iyerz.

Btw, sometimes in cases like these (No danger of flanking attacks), I actually try to overpower the opponent. I know that my players are cable of pulling something like this off, so in a last ditch effort during the match, I might switch things up with narrow-diamond style formations such as: 3-1-2-1-3 or 3-1-2-2-2 or 3-1-3-1-2 or 3-3-1-3 or any amalgamation of these.
Full central attack, up arrows on all players starting from the mid: MCs, AMCs and STs.
Attacking/Hard Attacking mentality.

You get the picture. But again it's all about how confident your team is against the opponent (If your goal line is not in danger then you may try to rush him/her hard - But be careful of counters ofc! Your opponent has stacked a lot of defense so who knows, he/she might be counting on stealing the ball during your attacks and going for counter plays through the middle).