"Ronaldo is one of the best players in the world," said the Bayern Munich full-back. "He has great pace, dribbles at you quickly, and he has a good finish with both legs and his head.
"He is a complete player and we have got to defend him as a team. You cannot go one on one against Ronaldo. Ronaldo is a sensational player so it is right to talk about him, but the team is focusing on their whole team and not just Cristiano Ronaldo."
Lahm will be relieved of much of the responsibility of dealing with Portugal's dangerman after confirming he will be playing wide left throughout EURO 2012.
The Bayern full-back started his career on the right hand side of the defence, but was soon moved to the left after a two-year loan spell with Stuttgart. He has spent much of his time with Bayern on the left before shifting back across to the right under Jupp Heynckes last season.
"It has been decided that I will play left," said Lahm during a press conference at Germany's base in Gdansk. "I have discussed it with the coach and he sees me better on the left."