You know, I have the same experience.. twice.. Losing 4-1 and manage to win 3-0 in my second leg. I sacrificed a little bit of my possession for strong, direct attacks. I used 4-3-3 with my own variation. Maybe you can try this.
---st--st--st---
---amc----------
-----------mc--
------dmc------
--dl--dc--dc--dr--

attacking, through middle, own half, normal tackling, long, zonal, no counterattack and no offside trap.. The key for this formation is a very strong amc and capable of scoring(better if your amc can shoot using both legs).. you can also put red arrows on dl and dr for all out attacks. If you decided to use this formation, be sure to use it 2/3 times before the actual match..