He said former Everton boss Roberto Martinez had “wanted me to play more as a target man” and added: “I learned it and for seven months I was unstoppable in the league, there was no way someone could hold me.
“But the last three months of the season, my level dipped and the team’s level dipped and it was sad how it ended with the former manager.
“With Mr Koeman it’s a change, it’s different. I know that if I don’t do what he wants me to on the pitch, I can go on the bench straight away. He keeps me very sharp and focused in the training sessions and throughout the games, which is going to help me.”
Lukaku said he aimed to produce “more match-winning performances” from Everton, who can go second in the table if they beat Crystal Palace at Goodison on Friday night.
And he added that he wanted to emulate players such as Manchester City’s Sergio Aguero and Bayern Munich’s Robert Lewandowski, who “can create a goal out of nowhere.”