Former Napoli player Ivano Trotta has already been won over by Rasmus Hojlund.
On-loan from Manchester United, Hojlund struck in victory against Fiorentina on the weekend.
Trotta said on Radio 1: "Hojlund is an extraordinary player. He impressed me against Fiorentina: he has incredible quality. The €40-45 million spent is justified, because we're talking about a promising young player, even if (Dusan) Vlahovic represented something more immediately ready.
"But in the end, I think things worked out well, because Hojlund proved to be a top-notch player, and for the price Napoli paid for him, they got a bargain. In 14 minutes, he scored a goal worthy of a top striker: it wasn't easy to read (Leo) Spinazzola's through ball and not be caught offside.
"He has the hallmarks of a top player; that goal was incredibly difficult, because the defender was coming back and he defended his position beautifully, maintaining composure to shoot close to the post.
"But what impressed me most was his ability to bring the team forward: when Napoli played vertically first time, he protected the ball and the defender couldn't anticipate him. This is crucial. He's a strong player with great prospects, and in my opinion Napoli paid very little for his value. Once again, they've made a great signing."