The Brit topped both FP1 and FP2 by a comfortable margin on Friday’s running at the Japanese Grand Prix.
“The Red Bulls were really quick here last year and naturally so, the Ferraris. So I wasn’t expecting that,” Hamilton said after the day’s action.
“I just came here with the mindset of I know where I’ve got to get the car, I know there’s always areas to improve.”
Despite the advantage that Mercedes have over their main contenders, the Brit is not letting up, saying he needs to keep improving.
“There’s two or three corners where I thought ‘I know I need to kill it this weekend’ and I got straight onto it,” he added.
“Straight away I was much, much better than I’ve ever been through those particular corners.
“So now I’ve just got to stay on it, keep going, keep working.
“We are working so hard to fine-tuning this car, which we are becoming accustomed to now and as I said I’m loving driving more than ever.”
Hamilton was not the only one to be slightly shocked by the big margin they had over the field on Friday.
Team boss Toto Wolff said the gap “flattered” Mercedes, but he did suggest that Ferrari had been running a conservative engine mode.
Meanwhile, the second Mercedes driver, Valtteri Bottas, finished in P2 behind Hamilton in both sessions.
He believes that come Saturday and Sunday, it always gets “more intense”
“It’s always so difficult to say it, from Friday,” the Finn said.
“Also, in Russia, it seemed that we were a lot ahead of everyone else on Friday, but in qualifying it gets more intense.
“Also with the changing weather, we’re not going into tonight thinking we’re comfortably in the lead or anything.
“We’re going to work as hard as usual to find all the improvements we can.”
Hamilton was fastest in both practice sessions on Friday, with Bottas in P2.