Cristiano Ronaldo has declared himself fit and ready to kickoff Portugal’s World Cup campaign against Germany on Monday. The current holder of the Ballon d’Or has been troubled with tendinitis in his left knee for several weeks, and, despite playing some part in Portugal’s final pre-tournament friendly against the Republic of Ireland last week, had caused further concern by exiting training early upon arrival in Brazil.

But after helping Real Madrid to Champions League glory last month, Ronaldo now states that he is ready to go for his country.

“I've been practicing now for some days and if I'm doing that it is because I am feeling well," Ronaldo said on Sunday. “If I am not ready I am the first to tell the coach I don't want to play and I can't play. If I feel anything during the match, which I am sure I won't, I'll be the first to say.”

Portugal enter the World Cup ranked fourth in the FIFA rankings, but if they are to justify that lofty position in Brazil the fitness and form of Ronaldo will be key. It was the 29-year-old’s hat-trick that ensured Portugal made it to the World Cup, with a superb hat-trick in the second leg of a playoff win over Sweden. Things have not gone to plan so far him at the World Cup, however. In 2006, he registered just one goal from the penalty spot before four years later he got an inconsequential goal against North Korea before Portugal exited limply in the second round.

With Lionel Messi making a dazzling first impression in Argentina’s win over Bosnia-Herzegovina on Sunday, the world’s attention now turns to see if Ronaldo can do similar. But, speaking before Messi’s goal, Ronaldo insisted he had nothing to prove.

“I don't think I have to show anyone anything,” he said. “If you look at my statistics and my resume...I have no words for that question. “I think I do not have to demonstrate anything, not now, before, not after. What I have to do is just continue my career, which has been great so far.”

Germany’s buildup to the competition has been blighted by an array of injury concerns. Marco Reus, Mario Gomez and Marcel Schmelzer have not even made it to the World Cup, while Bastian Schweinsteiger, Philipp Lahm, Manuel Neuer and Sami Khedira have all had varying fitness issues.

Joachim Low’s side are rated as one of the four leading favorites to lift the trophy in Brazil and end what for Germany has been far too long a wait for major tournament success, dating back to Euro 1996. Doubts remain about the makeup of Low’s lineup, however. In a signal of a change of approach, 36-year-old Miroslav Klose is the only recognized striker in the squad. The Lazio man will be desperate to get on the pitch, with his next goal taking him above compatriot Gerd Muller and level with Ronaldo as the leading World Cup goalscorer of all time on 15. It is likely, though, that Low will begin with a false nine. Either Mesut Ozil ot Mario Gotze could occupy the role, designed to help give Germany more control of the midfield and more possession.

Lahm could also replicate the midfield role that he has occupied to such good effect for Bayern Munich over the past season, meaning that the job of trying to shackle Ronaldo could be left to Jerome Boateng.

Where to watch: The 2014 World Cup Group G match will kick off from the Arena Fonte Nova in Salvador at noon ET. Coverage will be provided by ESPN, with a live stream available via Watch ESPN, ESPN3 and