Questions about the Real Madrid winger's fitness have overshadowed the Group G opener at Arena Fonte Nova, but he is adamant he is in good condition to make an impact.
The Real Madrid attacker has been struggling with both tendinosis and a thigh problem in recent weeks and was twice forced to cut short his participation in training ahead of his country's World Cup opener.
However, Ronaldo says that he is ready to lead Portugal into battle against Germany.
"The [fitness] problems are all in the past," he told reporters after training at Arena Fonte Nova on Sunday.
"Since the start of my career there's not been one single day in which I've played without pain. It's just the burden of my work.
"Obviously I’d like to be at 110 percent but I’m still at 100 percent and I think that’s enough to help that national team."
Ronaldo's availability is widely regarded as crucial to Portugal's hopes of upsetting Germany but the Ballon d'Or holder dismissed the suggestion that the Seleccao are reliant upon him.
"I don't believe that one player makes a team," the former Manchester United man declared.
"As I’ve said many times before, I’m just here to help. I can make a different in some games but I can’t carry the team on my back.
"So, let’s just go one step at a time. Tomorrow [Monday] we are playing on of the favorites, a team respect we greatly.
"We’re not one of the favorites but I think that’s good for us. It will allow us to give our best.”
Ronaldo has managed just two goals from 48 shots in his two previous World Cup appearances and there is a feeling that in order to seal his legacy as an all-time great, he needs to improve significantly upon those numbers in Brazil.
However, the 29-year-old attacker does not feel under pressure to perform.
"I don't feel I have anything to prove," Ronaldo stated. "I've already had a great career.
"And, for me, the pressure is something that pushes me on. I’m someone who likes challenges. I like to do my best, in La Liga, the Champions League etc. This is just a new challenge.
"Football is my life and I play it with a lot of passion. And that's why I seek my own new challenges.
"Now I’m in the World Cup and what I want to do is enjoy myself."