Davies told AVTV: "I have been impressed with Zat's performances against Hull and Arsenal - but I'm certainly not surprised. He's a top-quality player.
"The media this season have suggested that it is a three-horse race between myself, Martin and Carlos for those two spots in central defence. They have treated Zat like he's a non-entity.
"But he's chomping at the bit to do well for this club and now he's in, he wants to keep his place.
"He's done well and he'll be looking to impress the gaffer even more in the coming weeks. He won't want to give up his place so we'll have to be on their toes."