Sixteen-time Grand Slam winner Roger Federer still has plenty of goals he wants to achieve, and that ambition will keep him playing for a while longer.

"At the moment I am really, really motivated," the world No 3 said ahead of this week's Shanghai Masters.

"I'd love to win more titles. That's what I am playing for. I'd love to get back to world No 1, and in 2012 I can win the Olympic gold medal. As long as the motivation is there, I think I will play for a very long time."

The 29-year-old, who has enjoyed a glittering, 12-year professional career, still considers playing in front of a packed house great fun.

"It doesn't matter what I have achieved or what I want to achieve," he said. "I am excited to play in front of a sold-out crowd like here in Shanghai and that's what you want to concentrate on."

However, Federer is aware of the depth in the men's game right now and confessed the new generation of players is his biggest challenge.

The presence of Spanish world No 1 Rafael Nadal, who became the third-youngest man to achieve a career Grand Slam after winning the US Open last month, in Shanghai is daunting enough. The field also includes Serbian world No 2 Novak Djokovic, who defeated Federer in the US Open semifinals; Czech Tomas Berdych, who outplayed him in the Wimbledon quarterfinals; Robin Soderling of Sweden, who upset him in the French Open quarterfinals; and world No 4 Andy Murray of Britain, all of whom have shaken the Swiss star's supremacy over the men's game.

"The new generation is coming up," Federer said. "But as for the opponents, I am happy they are so strong because that makes me a better player.

"I think the men's side is very, very strong right now and it's very difficult to play in Shanghai."

Federer did not play in the Shanghai Masters last year, when Russian Nikolay Davydenko defeated Nadal in the final.

As he tries to win this year's edition, the Swiss can draw on previous success in Shanghai. He won back-to-back titles in the year-end Masters Cup, now the ATP Tour Finals, in the city in 2006 and 2007.

"I hope to win. That's why I am here," Federer said. "I always have a wonderful experience here and come up with some of my best tennis. I am very happy to be back in Shanghai."

Federer opens with a bye and will face John Isner of the US or a qualifier in the second round.