© Getty Images Enlarge Cristiano Ronaldo admitted he had to force himself to continue playing

Cristiano Ronaldo has admitted he took risks with his career by playing in Real Madrid's Champions League final last May and the summer's World Cup with Portugal.

Ronaldo struggled with a tendinosis issue in his knee and related thigh muscle problems through the final months of the 2013-14 campaign. While Madrid's medical staff reportedly wanted him to stop playing and allow the knee to heal completely, the player himself decided to "manage" the problem by only featuring in Madrid's most important games.

The current Ballon D'Or holder started the Champions League semi-final second leg against Bayern Munich, scoring twice in Madrid's 4-0 victory, and breaking the all-time record for most goals in a Champions League season. He was also in the team for the final against Atletico Madrid in Lisbon, when he was a peripheral figure for much of the game, but converted a late penalty as Madrid won 4-1 in extra time to lift the long awaited 'Decima'.

Ronaldo won't rejoin Manchester United Cristiano Ronaldo is happy in Madrid © Getty Images Real Madrid star Cristiano Ronaldo has no intention of ever rejoining Manchester United, his agent Jorge Mendes has told Spanish radio station Cadena Cope.

Ronaldo spent six years at Old Trafford earlier in his career and has been heavily linked with a return through recent months, but Mendes warned clubs interested in the attacker needn't bother calling.

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Asked by World Soccer magazine if he had put his career in danger by playing that final, Ronaldo said: "Yes."

He added: "In your life you do not win without sacrifices and you must take risks. We were taking part in big competitions and it was difficult. Things went well, I beat the record for goals in the Champions League. On holidays I rested and looked after my body. Sometimes I bring my body to the maximum, all elite athletes do that."

Ronaldo said he had "forced" himself to play through injury for both his club, and then his country's disappointing World Cup campaign in Brazil.

He said: "If I had stopped I would have been fine. I did not want to miss the final of the Champions League or the World Cup. I was not fully fit, but I forced the issue. On a club level it went well. We won, I scored and the team achieved La Decima, which was what we all hoped for. With Portugal it did not go so well."

Despite sitting out a number of Madrid's domestic games as their La Liga challenge faltered in the final weeks of the 2013-14 season, Ronaldo still scored 31 La Liga goals to win a third Golden Boot [an award he shared with then Liverpool attacker Luis Suarez].

"Individual prizes are the result of having achieved collective objectives," he said. "We had a fantastic season. We won the Champions League, the Copa del Rey and the European Supercup. A trophy like the Golden Boot is the prize for playing well as a team. I will not lie. I really wanted to win it."

Ronaldo also picked up a second Ballon D'Or award last January, after spectacular goalscoring performances for club and country during the autumn of 2013. Asked if the last 12 months had been the best of his career, his view was he had been playing just as well for many years now.

"Maybe it has been [the best] for collective or individual prizes," Ronaldo said. "But I have been at the same level for the last six or seven years."

With both he and Lionel Messi now frontrunners to claim the 2014 Ballon D'Or prize, Ronaldo said his rivalry with the Barcelona star was something he had grown used to and did not see as a major issue.

"This part of my life," he said. "It is normal that people compare us. I am used to it. It happened to me at United and I know how to manage it. We are colleagues. Outside of football I have no relationship with [Messi], but not with other players either. It is a positive rivalry."

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