Reflecting on the triumph and his effort, the England man laughed: "It’s been a long time coming to be honest!
"I should have scored a few in previous games and it’s nice to get one in a special cup."
City scored three times in a scintillating first-half display, thanks to a Yaya Toure penalty, Havard Nordtveit own-goal and a David Silva strike.
The Blues continued where they left off after the break, as Sergio Aguero climbed to third in City's all-time highest goalscorer charts and
"I thought we moved the ball well, first and foremost, and that got us the chances," the defender declared.
"We changed our system a bit, playing as a diamond with the front three. The overall performance was really good."
The defender was of course, also pleased to have denied West Ham a route back into the game.
"To get a clean sheet for us defenders, which we haven’t had too many of, we’re thrilled," he added.