(Adds new quotes)
LONDON Nov 3 There is no let-up for Roger Federer as he prepares for his 12th consecutive appearance at the ATP's season-ending extravaganza but the 32-year-old believes his old form is returning in time to end the year in style.
The oldest player in the eight-man ATP World Tour Finals draw and six-times former champion will begin on Tuesday against world number two Novak Djokovic, having come tantalisingly close to upsetting the Serb powerhouse in the Paris Masters semi-finals.
Wins over the big guns are becoming something of a rarity of late for 17-times grand slam champion Federer whose days of lording it over the sport may be over but whose box-office appeal is still as strong as ever.
For the first time in more than a decade Federer's place in the season finale was in jeopardy after a year, which by his own sky high standards has been lean, left him scrapping for points as the European summer turned to autumn.
Thankfully for the ATP, especially with British favourite Andy Murray absent after back surgery, Federer's strong run in Basel where he lost to Juan Martin del Potro in the final and again at the Paris Masters where he succumbed to Djokovic in the semis guaranteed his place.
The world number six may not be a title favourite when play begins alongside the River Thames at the O2 Arena, but few would wager much money against him producing a timely reminder of his powers as he aims to hold back the sands of time.
An opener against Djokovic is a tough proposition but Federer has twice won the title in two of the four years the tournament has been staged in London and he was clearly glad to be back when he spoke to reporters on Sunday.
"It's been a lot of tennis. I was hoping for that problem to occur so I'm happy it's gone this way," he said.
"It's clear these two days now are crucial and hopefully I'll come out on Tuesday somewhat fresh. I'm happy with my game and the confidence is back.
"I like this court. It has a great feel to it and usually I play good tennis here. I don't know what it is but usually it gets the best out of me."
Federer, who has won only one low-key title this year, faces a daunting task just to reach the semi-finals with Del Potro and Richard Gasquet also in his section.
Del Potro, who lost to Federer is Paris, had his possessions stolen at Paris's Gare du Nord on his way to London and will no doubt be keen to unleash his anger on Frenchman Gasquet who has qualified for the tournament for the first time since 2009 despite being ranked ninth - a beneficiary of Murray's ill-fortune.
"It's the first time something like this has happened to me. I'll try to enjoy the tournament and not let this affect me," Del Potro said about the theft. "I arrived to this tournament with the remaining energy I have."
Play begins on Monday in Group A with Czech Tomas Berdych, in his fourth consecutive appearance in London, taking on Swiss debutant Stanislas Wawrinka.
"When you step on court here at this arena, it's one of the best feelings you can get on a tennis court," Berdych said of a tournament rated not far below a grand slam in significance.
"It's very close to Centre Court in Wimbledon. This atmosphere is very special and unique."
World number one Rafa Nadal, who could theoretically lose his top ranking to Djokovic if he flopped badly at a tournament he is yet to win - a glaring omission from his CV - will begin on Tuesday against compatriot David Ferrer with the sour taste of his semi-final defeat in Paris still in his mouth.
"When he's playing well, he's very dangerous on all the surfaces, but especially on this one, because it's probably the worst surface for me," Nadal, who has won an incredible 10 titles since returning from a lengthy injury layoff in February, said after his Paris defeat.
Ferrer has faltered since reaching the French Open final in June but his win against Nadal on Saturday was one of his best career performances, even if he did go on to lose to the ominously clinical Djokovic in the final. (Editing by Ed Osmond)
Our top photos from the last 24 hours.