Lahm and his countrymen have defeated Ronaldo and co at the last three of the last four major tournaments.
Germany beat Portugal 1-0 in the group stages of UEFA Euro 2012, and also overcame them 3-2 in the quarter-finals of the same competition four years earlier.
Back in 2006, Lahm led his nation to a 3-1 victory over Ronaldo and Portugal in the FIFA World Cup third-place play-off.
FIFA Ballon d'Or holder Ronaldo - who made his comeback from knee and thigh injuries in a 5-1 friendly victory over Republic of Ireland on Tuesday - has a chance for revenge when the two countries meet in their 2014 World Cup opener in Salvador next week.
And Lahm has indicated the Real Madrid superstar will be determined to finally get one over on the Germans.
"With Ronaldo, I am taking it that he will play but it makes no difference to us," said the Bayern Munich skipper, who extended his contract at the Allianz Arena on Wednesday.
"He is an exceptional player but we are preparing normally as if he is going to play, as if he will be able to play and we think he will be able to play.
"For him too, it must be special to face us again, he must be desperate to finally beat us."
Despite the fact Portugal have not beaten Germany since Euro 2000, Lahm is not taking Paulo Bento's side lightly.
"Portugal played very well against us two years ago and with a bit of luck we were able to win," the 30-year-old added.
"They're a very good team, especially physically.
"I said after the draw that we would have to give everything in the first match and play well tactically because if we don't win, we will be under a lot of pressure. That makes the match with Portugal crucial."
