4-4-1-1

In the old days this has never been much of a problem to me. But recently, I played 4 times the same oppo who sticks to this whatever occurs. I won 3 and lost 1. But my problem is that he's ca. 30% weaker and that he dominated the last 3. What would be the solution IYO to solve the issue once and for all knowing that I DO NOT HAVE any ML/MR ? Thx.

What did you try?
I'd play 4-1-*, and set DMC defensively. The problem may be not in the formation, but in orders. I feel like orders are more important than formations.

the DMC is the key of your answer,

if you put weak DMC, you dead

I played 4-5-1V, 3W-2DMC-3W-1 (twice) and 3W-DMC-3MC-2WAM-1 (loss). Most of the times, I play normal/flanks with no counters (obviously, he plays defense).
I do not know what "weak" DMC means. He's 7 stars and was involved in all of my 25 successive wins.

Humm. 4-4-1-1 is one of my favs. Its my defensive version of 4-2-3W-1 hehe.
By the defensive side, 4-2-3W-1, 4-4-2 and 4-4-1-1 are weaker through the middle and stronger through flanks. So IMO, that's where you have to try. Maybe a 41212 or some variation of it. It has been a long time I dont face this formation, but old times I used to counter it with 3N-4-1-2 through the middle.