World No 1 Rafael Nadal pulled out of the season-ending Masters Cup on Monday because of injury.

The Spaniard was forced to retire from his Paris Masters quarterfinal against Russian Nikolay Davydenko last week because of a knee problem and said the packed tennis calendar had taken its toll on his body.

"I have decided not to compete at the Masters Cup in Shanghai," Nadal said in a statement on his website (www.rafaelnadal.com).

"I have mentioned on various occasions that the tennis calendar has been extremely hard with practically all weeks playing and where it forces players to compete week in week out, making it impossible for a top-level player to be 100 percent on each event," he said.

"Competing at so many events might have harmed, specially at the end of the season, my physical condition, taking away the freshness needed to play at the top level of the game on these last events."

Nadal, who the ATP said would be replaced in Shanghai by Frenchman Gilles Simon, said he was hoping to be fit for Spain's Davis Cup final against Argentina later this month.

"That is also another reason for not coming to Shanghai," Nadal said.

The Masters Cup starts on Sunday.

(Agencies via China Daily November 5, 2008)