The Chelsea striker is returning on-loan after a year away from the Nerazzurri.
"I really like Lukaku, it's wonderful that he showed so much desire to come back," Mazzola told FCinter1908.it.
“I understand some might struggle to welcome him back with enthusiasm, seeing what happened last year, but this is something never seen before in football.
“He needs to earn the affection back, working just as hard as he did the first year at Inter, so let's give him the possibility to do that."
Mazzola added: “I think he will do very well with [Simone] Inzaghi. He can still make the difference in Serie A and at the end of the day the only thing that really matters is that Inter win."