Roger Federer won his fifth season-ending title when he sailed past a seemingly tired Rafael Nadal 6-3 3-6 6-1 in the ATP World Tour Final at the O2 Arena, London on Sunday.

The 29-year-old Swiss stormed through the first set, before lulling down in the second allowing Nadal to comeback. However, Nadal was broken twice in the final set as Federer wrapped up matters in an hour and 37 minutes to win the last tournament of the 2010 season.

Nadal would have been hoping to add the only title missing from his career achievements but his three-hour semi-final with Andy Murray on Saturday seemed to have fatigued him, as evident from his show in the final set.

However, Federer's win can be looked upon as a statement by the Swiss that the Nadal's World No. 1 spot will be contested heavily contested next season.

Federer started the better with good serve and movement to keep Nadal on the defensive. Both kept serve, though Federer looked the less troubled. The decisive break came in the eighth game, when Federer's back-hand cross court winner had the O2 Arena in delirium as the Swiss moved to 5-3. He served out the next game to take the first set 6-3 in 32 minutes.

Federer had been offensive all through that first set, coming to the net whenever he could and not hesitating to hit deep.

Nadal, however, is nothing but offensive and he proved that in the second set. As Federer's first-serve percentage sank, Nadal powered through to break at 3-1. He then pegged Federer back taking his next three service games to level the tie and force the final decisive set.

Federer recovered his touch in the final set and took the initiative. In game four, the Swiss came from 40-15 down to break, helped by Nadal's two unforced errors. The next game was a nervous affair for both players, but the Swiss held on as he to keep the advantage.

From there on Federer looked in no trouble as he broke Nadal again when the Spaniard backhanded into the net twice. The World No. 2 sealed the victory in the final game with a deep forehand, leaping with joy as the London crowd went into ultrasonic.

After picking up a cheque for over $1m, the Swiss said, It's fantastic, I'm really thrilled the way I played all week. To win a fifth time is obviously amazing, for the third time in a different place. Like I said before, it would be great to win in Houston, Shanghai and also now here in London.

I'm just really happy the way I was able to finish the season in style, playing some of my best tennis, really saving the best for last. Obviously, beating Rafa in the final makes it extra special because of the year he had.

He only had words of praise for World No. 1 Rafa. I know I didn't spoil his vacation after this because he's had an amazing year, a year that any player dreams of.

Nadal, likewise, had praise for Federer as well, saying, He played unbelievable. I think in the beginning he was unplayable, the first set. I was still having chances in the second set and the beginning of the third, so-so.

My thought is he played better than me, he beat me. I can just congratulate him for his victory and another great tournament for him.

He played unbelievable all week, without losing a set, being in the final, so his level was very high. I tried my best this afternoon but he was better than me.

However, the World No. 1 evaded questions on how much his three-hour long semi-final with Murray on Saturday had affected him during the final. He said, I think it's not the right moment to talk about that. The thing is everybody saw the match yesterday, so everybody's free to think his own opinion. I don't want to say I lost the match because I was tired.

What I'm going to say and what I feel is I lost the match because I played against a very good Roger Federer on one of his favorite surfaces, and when he's playing like this it's very difficult to stop him.

It was a great finish to a wonderful year and 2011 promises another eventful season of top-class tennis.