Colwill was speaking ahead of Chelsea's Europa Conference League second-leg clash with FC Copenhagen tonight.
"I’ve enjoyed playing under him and I know everyone in the changing room does too," said the defender. "And over time you’ll see us getting better and better because of him. I’m always going to back the coach because I love how he wants us to play football. I love the ideas he has. I think he’s amazing.
"The ideas he brings in training to help us break teams down is all down to him.
"When we’re playing well and playing through other teams, of course, it’s partly down to us, but he sets us up correctly to look good on the pitch and score goals.
"I think in all the games where we have played amazingly this season, it has been down to him. Of course, we have amazing players who will help us pull off what he wants. But at the end of the day, it comes down to him.
‘As a manager and as a person he is top and he pushes us every day. He’s serious at times and he can also be a joker, so he’s got a great balance. And you don’t want to get on the wrong side of him!"
On his impressive passing game from the back, Colwill says Maresca is simply playing him to his strengths.
"I think the gaffer knows what sort of player I am and he puts me in a position where I can shine," the defender said.
"I think those passes come naturally when I have top players like Enzo (Fernandez) and Cole (Palmer) – the ones that play in the pockets in front of me – who understand the space in front of them and make it easier for me to find them. I think it’s really down to them boys."