Rafael Nadal confirmed that he was carrying a knee injury during his Shanghai Masters final loss to Roger Federer, but refused to blame the injury for his performance that saw him go down in straight sets to his long-time rival.

Nadal had almost blitzed through the field on his way to the final and was seeking his second title in China following his win in Beijing the previous week, but went down tamely 6-4, 6-3 to the Swiss ace on Sunday (15 October).

The world number one, who was seeking his seventh title of the season refused to blame his performance on his bad knee, which was strapped up. He also indicated that it was not a problem that concerns him, but hinted that he could skip the upcoming event in Basel.

Nadal was expected to play the remaining three tournaments in Basel, Paris and the ATP Finals in London, but his latest setback could see him focus his attention on the Paris Masters and the finals in the English capital.

"I don't want to talk about that [the strapping on his knee] now, sorry," Nadal said in his post-match press conference, as quoted by the Metro. "After losing final is not the moment. I am not worried, though."

"I don't know about Basel. I need to think about it. I cannot tell you now," the 10-time French Open winner added.

Nadal, meanwhile, thanked his team for always supporting him and playing a major role in his resurgence in 2017. It was almost exactly a year ago that Nadal ended his 2016 season prematurely due to a wrist injury, with questions being raised about his ability to return to his best and challenge for the major titles.

The 31-year-old has since captured seven titles, including a 10th French Open and a third US Open title among several other ATP titles. He is the favourite to end the year as the world number one, but Federer is still in contention going into the final events of the season. If Nadal skips the Basel Open, it will hand the Swiss star an added advantage in the race for the year-end number one ranking.

Rafael Nadal
Rafael Nadal has refused to blame his knee injury for his poor performance in the finals of the Shanghai Masters Getty

"This year for me has probably been the most successful year for me in China. Winning in Beijing and making the final here in Shanghai — it's been a great two weeks," the Spaniard said.

"I feel very happy for the things I have achieved after everything that's happened to me to be able to come here and do well — it's very important for me.

"Thanks to my team, they're always there for me and supporting me. There have been some tough moments over the last few years so to be here where we are today is fantastic," he added.