OK, I had the same problem at the start of my season. He went with narrow diamond and I went with 3-5-2V hoping I would score some goals but LOST 2-0 at his stadium. I had 55% possession and watched the match and he didnt. So very bad start to the season. So far, that is my only loss and I am on a 10 game win streak.

For some reason, I have probs vs Narrow Diamond. What the hell is the best formation to beat it?

On the point of watching matches...over-rated. You will hear from many people that managers who dont watch tend to win their games. I think the jury is still out on that though...

Let me know how you do vs the narrow diamond.