LONDON - Rafael Nadal admitted Friday that any chances he would have to overhaul Switzerland's Roger Federer at the season- ending ATP World Tour Finals are all but non-existent.
All it will take for the Swiss powerhouse to top the year-end table for the fifth time in six years is three group wins, according to ATP calculations.
The last showdown of 2009 starts Sunday with Andy Murray facing Argentine US Open champion Juan Del Potro and Federer to follow against Spain's Fernando Verdasco in Group A.
"I'm here to try my best, I have a first match against Robin Soderling," said Nadal, who plays Monday at the O2 arena.
"I don't think I have a real chance of taking number one. I would have to win the tournament and Roger would have to lose early or something.
"All the players here are good," said Nadal. "There will not be an easy match, so I can't talk about number one."
If Federer wins all three group matches, it's over for Nadal.
Federer could join Ivan Lendl as the only men to re-gain the top ranking after previously losing it.
The payday for an undefeated champion is 1.6 million dollars for a week's work on the indoor court. And that is the goal Nadal needs to strive for.
Federer stands 28-5 record at year-end finals, claiming four titles. Nadal, 4-4, played semi-finals in 2006 and 2007, losing both times to Federer, the eventual champion.
"I practised really well, I got info out of Basle and Paris which I hope will pay off here in London," said Federer.