The Real Madrid star left training on Thursday with ice on his troublesome left knee but team-mates Joao Moutinho, William and Eduardo all subsequently stated he would play in Salvador.
And Ronaldo confirmed his colleagues were on the right track when he spoke at Sunday's pre-match press conference.
"I have been training and I feel fine," he said.
"(It is) better not to have pain, but it has happened to me ever since I played football. It's part of the job."
Joachim Low's highly rated German side were among the pre-tournament favourites and Ronaldo feels that Portugal entering their opening game as underdogs could be beneficial for them.
"All teams have the ambition to win and we (have) also, but we have to think one game at a time," said the former Manchester United forward
"We have to be realistic and think this will be a very difficult group for us. We are not the favourite and it is also good for us.
"Every competition is a new competition for me and I always try to motivate myself at the start of any competition. I want to enjoy (the World Cup) and we have to push hard in order to win.
"We want to show our football to be able to beat a great team that is Germany."
Ronaldo and company have been rapturously received by locals at their training base in Campinas and the Ballon d'Or winner stated a victory would be dedicated to the Brazilian people.
"Many thanks to the Brazilian people that have supported us in Campinas and here in Salvador," he added.
"I hope this is reflected throughout the world and we feel a special affection in the stadium. We hope to reciprocate this support (by) dedicating them a victory."
