Germany v Portugal: Cristiano Ronaldo confident Portugal will enjoy a successful World Cup as he declares himself fit to face Germans

Ronaldo says his injuries are in the past and wants to improve on Portugal's recent showings in major tournaments

Cristiano Ronaldo believes he is in the best form of his career heading into the 2014 World Cup (Getty Images)

Cristiano Ronaldo says he has "nothing to prove" at the World Cup as his Portugal side prepare for their opening game against Germany.

The Ballon d'Or winner has been struggling with knee and thigh injuries recently but is expected to captain Paulo Bento's side in Salvador later today.

His record at international level is way off his blistering club form - Ronaldo may have more goals than appearances for club side Real Madrid, but he has just two goals in 10 World Cup matches so far in his career.

Now 29, Ronaldo is expected to be near the scoring charts in this tournament, though Portugal have arguably the toughest group in the tournament with Germany, Ghana and the USA also in Group G.

"If you look at the last few years, they have all been similar years, so they have all been the best of my career," said the former Manchester United star.

"But I feel I am in the best moment of my career and I want to continue that moment and enjoy it. I want to be champion but let's take it a step at a time.

"This is a different tournament to 2006 and 2010. There are many new players but only at the end will we know.

"But we have many good players and I believe we will have a good World Cup."

Despite the persistent injury problems that caused him to miss two of Portugal's warm-up matches and play well below his best in the Champions League final, Ronaldo has declared himself fully fit.

"The problems are all in the past," he added in a pre-match press conference.

"If I feel something, and I am sure I won't feel anything during the game, I will not risk my career. I come first and not football.

"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.

"I'm ready, I'm feeling well. I don't have anything to prove. One player is not a team, I can't carry the whole team on my back."

Despite his dreary World Cup record, Ronaldo scored three goals at Euro 2012 to lead Portugal to the semi-finals, and scored all four goals in the two play-off matches against Sweden. He now has 49 goals in 111 international matches.

"I don't think I have to show anyone anything. Look at my statistics and CV - I have nothing to prove.

"My career has been great so far and I just want to continue."