How to counter this rare formation?

Thanks!

that is not rare ..
my friend used it last night and beat him away 4-1 easily with us almost same level

better go for 4141 or 451V or a mix of those 2 (one winger stay at mid the other (better one) move up)
attack his weakness in flanks, hard defending, long balls, counter

blue arrow on DMC to protect or red if you need to attack
St, wingers and RB,LB red arrow

replace ST and wingers by 65-70 min as they will be tired bcz of red arrow

Too vulnerable through the flanks.

Attack him down both flanks, stay normal or defensive and set pressing style whole pitch.