He is affectionately known as the 'Water Carrier' at Villa Park.
Lambert said: "I call him that but it's the biggest compliment I can pay him. He's brilliant at it. He does the hardest thing well, which is just keeping the ball. The thing is, he never gives the ball away. I know exactly what I'm going to get with him.
"Coming from where he was and to do what he has done here is absolutely phenomenal. Players like Christian Benteke get all the headlines and I suppose a lot of the work Ashley does goes unnoticed by some.
"But not by me. The team functions when he's getting the ball and giving it. He's been great.
"I think that maybe now, with the way he's playing, he's finally starting to get the recognition he deserves."