The 16 year-old striker scored on his debut in Roma's Coppa Italia defeat to Torino.
Giuseppe Pesce, Arena's agent, likened the youngster to Michael Kayode, who Pesce moved from Fiorentina to Brentford a year ago.
He told TMW: "We know this is the first step, but at the same time we're also very happy and proud of him, a professional and an incredible guy.
"There's a lot of work to do, but his emotional intelligence and humility give us hope. He reminds me of Kayode in terms of his dedication and mentality; he's someone with the mindset to become a top-level footballer.
"He's mature for his age. We have a team that works continuously, taking care of scouting and data, which we then combine on the pitch. Our players are talented, but courage is lacking in Italy, and that's crucial."
Arena, born in Australia, is an Italy U17 international and moved to Roma last sumer from Pescara.