Counter Discovered: 4 - 2 (MC) - 3W (AML,AMC,AMR) - 1
So I lost the first game against this guy 3 : 0 at home, I figured it was over and I went for an all out attack for the next away game against him. Note that our teams' quality is almost exactly the same (both lvl 28, both around 155 average quality). I won..wait for it..7:0!! He had absolutely no chance, maybe one good opportunity and didn't otherwise pass the center of the field. Again, we have the exact same player quality and the exact same players and formation (I changed my formation, obviously) was used in both games. So, the first game I started with Narrow Diamong, he scored a goal, I went for 4-5V-1, he scored 2 more goals. The key isn't in the formation, tho.. The key is in the tactics..
For the second game I used 4-5V-1, but with these tactics: (I figured I have nothing to lose so I went all out attack)
Hard Attacking (yes, HARD ATTACKING biatch :D)
Whole Pitch Pressing
Down Both Flanks
HARD Tacking
Offside Trap (I have good defenders, about the same quality as his attackers except for his one AMC who is overpowered)
RED ARROWS on: DL, DR, AML, AMC
It WILL work for you in 99% cases, because he only had like one chance, and that 1% chance of you losing with these tactics are because you might miss all of your chances, and he might score from one attack in the entire game. Rare, but happens.
I hope I helped!
TL;DR; COUNTER FORMATION FOR 4-2(MC)-3W(AM)-1 is 4-5V-1 with hard attack, both flanks, whole pitch pressing, offside trap and (optional) hard tackling - I used hard tackling since it was a home game.