LONDON:Rafael Nadal said he was going work hard on regaining his self-belief and sharpness in a bid to reclaim the world number one spot from Roger Federer next year.

The Spaniard said it was time to head for the practice courts to make sure his game was back to his best for the 2010 season.

Nadal was eliminated from the season-ending World Tour Finals at London's O2 Arena -- the showdown between the year's top eight players -- losing 6-1, 7-6 (7/4) to Russia's Nikolay Davydenko in the group stage on Wednesday.

"I didn't arrive to this tournament with the full confidence that you need to win these matches. And in the moments that I had to play well, I didn't play well. I had mistakes," Nadal admitted.

"The season is done, and I am playing difficult surfaces for me. When the season is going to start next year, probably I am going to play a little bit more favorable surfaces for my game.

"Practising and working a lot, that's the way for me, the only way to improve the situation. That's what I did all my life."

Nadal is due to contest the December 4-6 Davis Cup final, in which Spain host the Czech Republic in Barcelona.

But after that, the 23-year-old will head back to his native Mallorca to work on improving his game -- and the left-hander is up for the challenge.

"I have motivation to play my best tennis again. When you have this goal and you have this motivation, it doesn't matter if you are tired or not. So I am ready to start practising and to start playing in 2010," the Australian Open champion said.

"I don't know how far I am from my best. The important thing is, when this change can happen, be ready to do it."

Nadal's loss to Davydenko followed a straight sets defeat to Sweden's Robin Soderling, who has secured a semi-finals spot.

"I have to play again with this intensity, with this full rhythm with my forehand, playing without mistakes, playing this intensity that the other ones can't attack you, so you can have the control of the point, but without a lot of risk," Nadal said.

"And play 10, 12, 20 shots with the confidence, without thinking if you are going to have a mistake or not. So that's the goal right now.

"The serve is the thing I still have to improve, always. But that's not going to be a big change on my serve. But I still have to work hard on my serve, to serve a little bit faster with a little bit more high percentage."

Group B's second semi-final berth will go to either Davydenko or Serbian titleholder Novak Djokovic. In the final round of Group B games Friday, Davydenko plays Soderling, while Nadal faces Djokovic.

Davydenko said he was not bothered if people do not give him the respect he deserves as one of the game's top players.

"That way I have no pressure and I can play my tennis. I show my best tennis and I'm winning. If nobody's waiting for it, maybe it's good for me and easier to win a tournament," he said.

Davydenko won 14 out of 16 points at the net against Nadal and the Russian is keen to keep charging up the court.

"I want to prove my tennis. And for sure, for every match in the future, I want to play volley, come to the net.

"It's a good idea, make a good serve, play in the net, good volley, it gives me much more confidence.

"And I hope for the future, this give me really a chance winning easy points, what I didn't make before. Maybe because now I'm 28 years old, I need to do something."