Ronaldo struck in their 3-1 win over Real Zaragoza.
Karanka said: "We are all well aware of Cristiano's characteristics.
"His experience allows him to grow and adapt to the team's necessities. We know how the Bernabeu crowd is and what it wants. They weren't much in favour of him not so long ago and tonight they gave him a standing ovation. He played at a high level. It's better to grow and if a player of his quality manages to grow then it's great for the team."