The former Empoli defender made the move over the summer for close to €10m, but had not played a single minute for the Partenopei until tonight.
“I had to get over a few fitness issues, but working hard I was fortunate enough to be ready at the right moment," Tonelli told Sky Sport Italia.
“It's an unforgettable night and incredible to score this goal. When people say you have childhood dreams come true, they mean a night like this!
“In the first half we struggled to put passes together, but we did well not to let our heads drop."