Need some help against a squishy team

In 3 hours I will play the second leg in Champions League and the other team is really strange.He is playing like this:

----ST--ST----
---------------
ML--MC-----MC----
--------DMC--------
DL--DC--DC--DR

I've tried something similar in yesterday league match against a 3-4-3 formation, I was spectating the game, but in 20 minutes it was 20%-80% possesion for the other team.
In the first leg i played 4-5-1 V style and lost 2-1 at home (also i had possesion and more chances than him).The quality of the teams is balanced...

Can somebody help me?:(

a 20/80 possession means someone had an illegal formation. Depends on your team, but i would say 4-2-2-2 hex or 4-3n-2w-1. attack those flanks