That's a strange formation, [MENTION=19733]Mido[/MENTION]. A big gap in the middle.
Just to mean that Denis can go wide when Messi penetrates the midfield in order to find spaces when he smoothly sets up the build-up and Gomes may play also as the second pivot if/when Atletico is pressing.
it could also be put as
---------Mascherano---------
---Denis-----------Gomes---
-------------MSN--------------
or
---Mascherano-----Gomes---
--------------Messi------------
---Denis-----------------Neymar
----------------Suarez-----------
if you wish.
I believe denis playing as the "offensive pivot" in a reverse triangle is risky, Messi should assume this role and Denis should go on the right wing.