World number two Rafael Nadal [Images] said on Monday he is still a long way off catching Swiss master Roger Federer [Images] at the top of the world rankings.

French Open champion Nadal paid tribute to Federer's successful defence of his US Open [Images] title at the weekend but the Spanish teenager believes he has time on his side.

"Roger Federer is the best player in the world. He wins everything," Nadal told reporters in Beijing [Images] at this week's China Open.

"He's lost only three matches this year. It's amazing. I can't be number one this year but I'm still very young. I'm 19 years old and I have many years to be number one."

Nadal has won nine ATP tour titles this year -- just one fewer than Federer -- but is looking to bounce back quickly from his shock third-round exit at the US Open.

"I'm still happy with my season," said Nadal, who plays Taiwan's Wang Yeu-Tzuoo in his Beijing opener on Tuesday. "I've won a lot of tournaments and that gives me confidence. I'm improving every year. It's a normal evolution."

Nadal has already qualified for the year-ending Masters Cup in Shanghai but he pledged to try and prove he is more than a clay court bully for the rest of the season.

"I know I can play well on hard courts," he said. "I won in Montreal and I've won a lot of matches. It's just my mentality. I need to be more aggressive, especially on grass and indoors.

"What's most important to me now is to improve and improve."

Argentina's Guillermo Coria and David Nalbandian, as well as fellow Spaniard and mentor Carlos Moya [Images], are among those who stand in Nadal's way at the $1.1 million China Open.

The women's tournament begins on Monday with five of the world's top 10 players involved.

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