Ronaldo has 23 goals in all competitions so far this season, matching his total for the whole of last season, though Ferguson is less surprised about that.
"You could say I'm pleasantly surprised, but after what we have already seen it is not a total surprise," the manager says. "He's a good finisher, with all the quickness and bravery a striker needs, and he's at an age where he is still improving.
"He loves the game and he loves scoring goals. Every kid does. He found out he could score goals - we didn't demand that of him. It was a natural progression. I did set him the challenge of scoring more than he did last season, but I won't be revising the target. He's achieving plenty for us at the moment so we'll just let him carry on."