The 48-year-old Dutchman was appointed as Steve Cooper’s successor in November 2024, with the Foxes seeking to salvage their struggling 2024-25 campaign.
In addition to chasing all three points, Sunday’s league clash between Chelsea and Leicester City will see the Italian reunite with his friend at the King Power Stadium.
While emphasizing the importance of securing a result against the Foxes, Maresca revealed the role he played in convincing van Nistelrooy to take up his current job."Ruud is a friend of mine after we played together and after that, we have stayed in contact," the Blues boss told the Chelsea website.
"So when Leicester called (Ruud about the job), he called me and I just said Leicester is a fantastic club. So I told him many positive things about Leicester."
On the mission to Leicester, he added: "The most important thing, let me say, is that we need our fans on Sunday for 90 minutes or 100 minutes. We need to win the game.
"They were there with us supporting the team in Copenhagen, and now the most important thing is Sunday’s game.
"We need them because winning on Sunday can take us one more step towards our target."