I don't think he's either tbh. If he was clutch he'd have scored that late chance against Barca at home. He's scored big goals against Lazio twice, and maybe you can count the Turin derby, even if they are an average team.
He seems to go on spells of scoring goals. Obviously his injury came at the end of a lean spell this season so let's hope he hits the ground running with these goals because when he's on form you think he will score every shot. As he gets older the goals should become consistent from a player of this quality.