Wimbledon champion Rafael Nadal said on Monday he had pulled out of this week's Stuttgart Cup tournament due to a knee injury.

"My doctors have said I need a couple of days rest. I will now get examined for an exact diagnosis," the Spaniard told a news conference in Stuttgart, adding he had a problem with his knee without providing any details.

"I only want to return to the court once I am 100 percent fit," the 22-year-old said.

Nadal, four-times a French Open champion, became the first Spaniard in more than four decades to win the Wimbledon men's singles title on Sunday after defeating Roger Federer.

"It was amazing for me," said Nadal. "It was a very special victory for me winning against Roger and the most important thing winning Wimbledon."

Asked what the victory meant to him, he said: "Right now I only think about the present. Probably when I finish my career, I am going to think about these things."

Nadal, who has twice won the Stuttgart Cup, said his immediate focus was to get some rest. "My future plan is to relax. I played for the last four or five months without stopping...I need to recover. I have to work with my physio and work with my doctor."