On-song Federer targets record in London

Roger Federer will aim to finish an off key year on a high note by winning a record sixth title at the ATP World Tour finals which start on Sunday at London's O2 Arena, a venue more famous for staging the biggest acts in the music business.

The world number four, who opens round robin action in the defence of his crown on day one against dangerous Frenchman Jo-Wilfried Tsonga, is level in the season-ending tournament's roll of honour with Ivan Lendl and Pete Sampras.

Despite being the oldest player in the eight-man draw, and arriving with his lowest ranking since 2003, few would bet against the Swiss 16-times Grand Slam champion supplying a show-stopping end to a year dominated by Serbia's Novak Djokovic.

Now in its third year beside the River Thames, the appeal of the tournament has never been higher with more than 250,000 people set to watch eight days of action at the event often dubbed the "fifth" Grand Slam.

"That's like the equivalent of 15 back-to-back sold-out Beyonce concerts," managing director Chris Kermode told Reuters by telephone on Thursday as work continued to turn the O2 into one of the most spectacular venues for tennis in the world.

"We have set the bar every high and we are lucky that we're hosting the tournament in the golden era for men's tennis.

"Often generations have one star player and a supporting cast but we are blessed with four marquee names in Federer, Rafa Nadal, Novak Djokovic and Ands Murray and then players like Tsonga who is very popular with British fans."

While Federer, like American soul diva Beyonce, just turned 30 and has fallen behind Djokovic, Nadal and Murray in the rankings after a rare year without a major, he is still the biggest draw in the sport.

Successive titles in Basel and Paris in the run-in to London, surprisingly the first time he has won back-to-back tournaments since 2006, proved Federer's mercurial game and remarkably injury-free body are in good shape as he prepares for his 10th consecutive appearance at the season-ender.

With serious questions over the state of Djokovic's serving shoulder and Nadal, who is also in Federer's group along with American debutant Mardy Fish, not enjoying his best year away from his beloved European claycourts, the Swiss is arguably the favourite to claim the title again.

Djokovic, who is a group with Murray, Czech Tomas Berdych and Spain's David Ferrer, looks to have hit the wall after lifting three of the year's four grand slam titles and seizing the number one ranking.

Home fans will be hoping world number three Murray can land the biggest title of his career, having lost a three-set semi-final classic against Nadal last year.

Murray, who reached at least the semi-finals of all four Grand Slams this year, appears the most likely player to prevent Federer setting yet another record.

The Scot, who begins his Group A matches against tenacious baseliner Ferrer on Monday, went on a red hot 17-match winning streak after the U.S. Open -- a run snapped by the clean-hitting Berdych in Paris last week.

Outside the big four, Tsonga could be the surprise package, having stayed clear of the injuries that have blighted his career to qualify for the season-ender for only the second time and the first time since 2008.

"I'm not going to be turning up just thinking it's great to be here and I'm just glad to participate," the Frenchman said after the draw gave him an immediate chance to avenge his Paris Masters defeat by Federer.

Those sentiments were echoed by Fish whose rise into the top eight as Andy Roddick's career goes into decline ensured a 25th consecutive year that an American will take part in the tournament which has swapped venues regularly over the years but now seems to have found a natural home in London.