"I have decided not to compete in the Masters Cup in Shanghai. As I say this is one of the most difficult decisions in my career due to the importance of the event"

World number one Rafael Nadal of Manacor said on Monday that he had pulled out of the season-ending Shanghai Masters due to fatigue after a long season and to focus on the Davis Cup in Argentina.

“I have decided not to compete in the Masters Cup in Shanghai. As I say this is one of the most difficult decisions in my career due to the importance of the event,” he said in a statement posted on his official web site.

The 22-year-old, who had to pull out of his Paris Masters quarter-final on Friday with a right knee injury, said it had been “a long and difficult year” which had left him without “the freshness needed to play at the top level of the game on these last events.”

“I want to recover and be ready for the important Davis Cup final with my country that will be played in Mar del Plata, Argentina. That is also another reason for not coming to Shanghai,” he added.

Nadal’s place at the November 9-16 Shanghai Masters would likely be taken up by France’s Gilles Simon. The Davis Cup will be held between November 21-23.

The tennis ace, who owns eight titles from 2008 including the French Open, Wimbledon and the Olympics, said he expects to take part in the ATP Masters event in Shanghai in October 2009.

“On a personal level I had as one of my goals to become number one during this year and competing at so many events might have harmed, especially at the end of the season, my physical condition,” he said.