O'Reilly has been outstanding at left-back for City this season.
The youngster told City's website: “It’s easier when you’re playing with players that you play with every two or three days - you build connections and relationships with each other.
“I’ve got Josko (Gvardiol) next to me most of the time and I know if I jump up, he is there to cover me and vice versa. The relationship I have with Jez (Jeremy Doku) too - if he wants to go inside, I’m outside and the other way too. It’s all clicking nicely.
“We’ve realised each other’s strengths and we work off each other. Everything has come pretty naturally - all the games come so fast and we’re all playing so many minutes. When it’s like that, it’s easier to understand each other.
“As soon as we’re around the goal, we know where Erling (Haaland) is going to be, we know what the wingers can do, Phil (Foden) has found his spark and he’s on top form.
“This is what we needed - we needed players to step up like that. We’re in great form and we’re doing very well.”