Diaz is among those Reds players to have thrived this season under Slot in his first campaign as manager.
"Arne Slot has dropped really well into the club," he told the club's website.
"He has known exactly how to handle the group and every single player he has in the squad, because it can't be easy for any coach when he has two or three excellent alternatives for each position on the field.
"It's not an easy task, but he's done it, and he's also given confidence to every player in the squad."
Also tactically, Diaz is impressed.
"He has implemented some very important things for us tactically. He is really proficient in that area and he will also direct you and tell you what to do when he feels there is a need for it. So that's how it is. He manages the group really well."