Snapped up in January from Atalanta, the 18 year-old striker told the club's website: "It was great to make my debut at St.James' Park and hopefully I will continue to play for the reserves this season.
"I'm enjoying life in Newcastle and have settled in really well."
Meanwhile, second-string coach Adam Sadler added: "Fabio had an impact when he came on and caused a few problems and probably should've scored.
"But he's been fine so far and has settled right into it.
"In fact, he's already telling me that he's an adopted Geordie so I think he's definitely enjoying himself!"