It looked like a pretty fixed diamond to me. We basically had McTominay playing right on top of AWB and Pogba right on top of Shaw. Add Fred into the mix playing as the point of the diamond and we basically had 7 outfield players within 35yrds of our goal most of the time. This just played right into Arsenal’s pressing gameThe diamond is effectively a 532 or 352 in transition if you have the players.
The full backs need to provide the width and the defensive midfielder needs to have the nous to drop deeper when the full backs are upfield.
It’s a very flexible system. Labelling it “The Diamond” is too reductive.