AFP

Shanghai, Nov 7: There's no Rafael Nadal, but Generation Next poses a serious threat to Roger Federer's tilt at a Tennis Masters Cup hat-trick from Sunday. 

Britain's Andy Murray heads a list of four new faces, including Jo-Wilfried Tsonga, Juan Martin del Potro and Gilles Simon, at the least predictable season finale of recent years.

Murray is the man in form after a breakthrough spell in which he reached his first Grand Slam final and won back-to-back Masters series titles to go fourth in the world rankings.

"Since Wimbledon I've played the best tennis of my life, and hopefully I can keep it going," said the 21-year-old Scot.

Federer is chasing the first year-end title hat-trick since Ivan Lendl in 1985-1987 and his fifth Masters Cup overall at the end of a difficult year.

But the former number one's bid could yet be undone by a stiff back which forced him to pull out of the Paris Masters quarter-finals a week ago.

Top-ranked Nadal has already disappointed Chinese fans by withdrawing, variously citing fatigue, tendinitis and the need to prepare for this month's Davis Cup final.

Murray and Federer are drawn together in Red Group along with American Andy Roddick and France's Simon, a late replacement for Nadal.

In Gold Group, world number three Novak Djokovic is favourite to finish top ahead of Russia's Nikolay Davydenko, Tsonga and del Potro.

The new faces suddenly make Federer, 27, one of the old guard, with Davydenko just a couple of months older and Roddick clocking in at 26.

The top seed was all but written off when he lost his Wimbledon and number one crowns, both to Nadal, but he showed the familiar magic in winning his 13th Grand Slam title at the US Open.

He has a breathtaking record at the Masters Cup, reaching the last five finals and losing only one, when he was hampered with an ankle injury against David Nalbandian in 2005.

But the Swiss has shown rare vulnerability this season and has lost his most recent matches against Murray, Simon and Roddick.

Djokovic will now be targeting Federer's second ranking after hammering home his Big Three status by winning the Australian Open and Beijing Olympic bronze.

The 21-year-old Serb opens the tournament on Sunday against Argentina's del Potro, barely out of his teens, who caused a sensation mid-season by reeling off his first four titles back-to-back.

Tsonga, 23, muscled his way into the draw with a home win in Paris, rounding off a regular season in which he spectacularly floored Nadal to reach the Australian Open final but also had three months out injured.

"It's an amazing turnaround," he said. "Less than two years ago I was ranked 250th in the world and I was playing in small clubs in small tournaments and I really wanted to get up to this level one day.

"Now here I am heading for Shanghai to play against the best players in the world."

Tsonga faces Davydenko in Sunday's other match. The Russian, cleared of corruption allegations in September, reached Shanghai for the fourth time in a row after bagging three titles in another consistent season.

On Monday, Federer starts against Simon and Murray will play former number one Roddick, who is appearing for the fifth time and has reached three semis.

The showpiece event, featuring the top eight players, is making its fourth and final appearance at the futuristic Qi Zhong Stadium before moving to London as the ATP World Tour Final.