Erling Haaland’s double, after Rodri’s first goal of the season had given City an interval lead, ensured a routine victory before Pascal Struijk headed a second-half consolation for Leeds.
Lewis turned in another assured performance which belied his 18 years after starting in last week’s Carabao Cup win against Liverpool, but revealed he did not yet feel a part of the first-team set-up.
“No! It’s still like I’m just playing with them,” he said. “I don’t feel like a first-team player.
“I’m doing my best to keep up with them and put in the best performance to help them win.
“I don’t know when I will feel like a first-team player. It will just slowly become natural, I don’t think there will be a turning point.”
City’s win lifted them back into second place above Newcastle and to within five points of leaders Arsenal in their bid for a remarkable fifth league title in six years.
But Lewis stressed his own ambition this season did not extend beyond retaining his place in Guardiola’s plans.
He added: “If (another title) comes with it then it’s a dream come true, but for me it is playing and performing as well as I can.
“When it gets tough, carry on, when it’s going well, carry on. It’s not about winning, it’s just showing what I can do.
“Seeing players like Phil (Foden) and Cole (Palmer) come in and do it gives you more hope as you’re coming through and drives you on a bit more.
“You know it’s an achievable thing, so it pushes you on a bit more.”
Leeds slipped to their eighth league defeat of the season and remain in 15th place, two points above the bottom three.
Jesse Marsch’s side worked tirelessly to contain City at Elland Road, but were undone by the gulf in class and face a quick turnaround before another difficult challenge at high-flying Newcastle on New Year’s Eve.
Marsch, whose side have three days to recover, said: “It’s obviously not the best situation, when the schedule comes out and then they change our matchday and then we know we have three days’ rest and Newcastle have five.
“By the way, Newcastle and us are the two most intensive teams in the league. We know that the turnaround is going to be important and demand is going to be high for us.
“We’ve a lot of respect for the way Newcastle play, the results that they’ve got and the job that the manager has done, so we know we’re in for another really tough match come Saturday.”