The Azzurri won 2-0 via goals from Osimhen and Lorenzo Insigne.
“It's not about numbers, but the principles of football," Gattuso told DAZN.
“We know Osimhen is an added bonus, but we need to run before we have quality, because quality is not enough on its own. We must set out the team with the right concepts and protect the defence, but we knew that Osimhen could give us another gear in the final 20-25 minutes today.
“Osimhen is a lad who, in the 25 days I've been working with, I can tell doesn't forget where he started from, who made sacrifices, lost his family very young and has the head of a 40-year-old on 21-year-old shoulders.
“I am confident he won't change, as he has a great attitude and at this moment is a better player than he's so far shown on the pitch."
“Playing with Fabian Ruiz and Piotr Zielinski in midfield with three or four forwards ahead of them… When I was a player, I was happy just keeping a clean sheet, but I want more entertainment now that I am a coach.
“It's not really something I am accustomed to and I envy those coaches who know it well.
“When it comes to coming back to get the ball, Fabian Ruiz is one of the best. Playing a two-man midfield, he needs to improve the way he covers the space and moves around the pitch."