Inter meet Napoli on Sunday, with Conte full of praise for Koulibaly.
Conte said, “He is one of the top two or three defenders in the world and I wanted to bring Koulibaly to Chelsea. He's actually improved since then.
“Lukaku has improved a great deal too, it'll be an interesting duel, but both sides will have to work as teams to create goal-scoring opportunities."
He added: “We mustn't fall into the trap of taking the Scudetto for granted, because it hasn't been assigned yet. We know the sacrifices we've made to reach this position, but must be humble to realise there are still some steps to go before we can make that dream come true."