By Abhishek Mehrotra
On the face of it, there is very little left to play for in London. Roger Federer's decision to withdraw from the Paris Masters deprived the tournament of its most intriguing sub-plot - the race to end the year as number one.
Apart from the possibility that David Ferrer might overtake the injured Rafael Nadal as the world number four, and minor shuffling of numbers six through eight, the points gained by the players will be of little significance in the short term.
As the quality and depth of the men's field has improved though, the World Tour Finals have taken on an added significance - suitably emphatic exclamation marks to seasons that have inevitably been thrilling. US Open champion Andy Murray recently said that from the players' perspective, the year-end carnival is only behind the Grand Slams and the Olympics in prestige.
This year will see the Janko Tipsarevic make his debut in London thanks to a string of consistent results and Nadal's forced withdrawal. Juan Martin del Potro makes a returns for the first time since 2009, a measure of how far he has come since the wrist injury that threatened to end his career.
Novak Djokovic, Andy Murray, Tomas Berdych and Jo-Wilfried Tsonga make up the rest of the field. Here's a look at the respective groups and which players are likely to progress through to the knockout stages.
Group A: Djokovic, Murray, Berdych, Tsonga
Undoubtedly the trickier of the two groups, with two Grand Slam winners paired with two of the tour's most dangerous floaters. Djokovic was the man in form after the US Open, until he unexpectedly lost to Sam Querrey in the second round of the Paris Masters.
It is difficult to think though that the result was anything but a blip in what has otherwise been another great year for the Serb. He'll start as favourite to top the group.
Murray also suffered a major reversal in Paris, losing to the red-hot Jerzy Janowicz at the same stage. After his breakthrough US Open win, Murray has lost thrice having held match points in all three matches.
The losses to Milos Raonic in Japan, Djokovic in Shanghai and then to Jancowicz in Paris all pointed to a worrying trend, but with coach Ivan Lendl back in his corner and vociferous home support to bank on - the Brit will have every chance of ending a sparkling year on a high. He should qualify for the semis along with Djokovic.
Berdych and Tsonga are a threat to any player on their day but continue to suffer from an inability to carve out the big results on a consistent basis.
Berdych lost to Murray at the US Open after beating Federer, was routed by Djokovic in Shanghai, took the ATP 250 title in Stockholm by beating Tsonga before being upset by Gilles Simon in Paris. He'll give both the higher seeds a run for their money, but is unlikely to upset either.
Last year's finalist Tsonga has had an even patchier end-season. A second round upset in New York, a title triumph in Marseille, a final defeat to Djokovic in Beijing and a quarters reversal at the hands of Ferrer in Paris. Plot his results and it'll resemble an ECG. Expect plenty of showmanship and some thrilling play from the Frenchman. Ultimately though, he'll fall in the group stage.
Group A Prediction
Group B: Federer, Ferrer, Del Potro, Tipsarevic
Despite having lost to Del Potro in the Basel final recently, Federer is the runaway favourite at a tournament he has already won a record six times, including twice in succession at the O2 arena, in 2010 and 2011.
The Swiss, who was last week dethroned by Djokovic as the world's top player has had an underwhelming few months with losses to Berdych, Murray and del Potro meaning the 2012 fall season has been a far cry from the barnstorming run he had last year.
Yet, he seems to relish playing indoors in London and is on a ten-match winning streak at the O2. He's likely to be troubled by Del Potro, but should get past the powerful Argentine. Ferrer and Tipsarevic should not pose a threat - the duo have faced Federer a combined 17 times, and have yet to emerge victorious.
Del Potro and Ferrer are likely to fight it out for the second qualifying spot and based purely on recent results the Spaniard's case appears to be stronger. Ferrer won the ATP 500 tournament in Valencia before taking his maiden Masters title in Paris on Sunday. Tiredness might have played role with any other player, but Ferrer's fitness levels are legend - he should be charged up under the lights.
In what will be a classic match-up between defence and offence, the world number five should just about get through.
Tipsarevic has had a steady year without any truly stunning results with the exception of a win over Djokovic at the Madrid Open earlier this year. He was also within a few points of reaching the US Open semi-final, but fell to Ferrer in five. He'll pose a few questions to the Spaniard yet again, but does not possess the weapons to depose Del Potro or Federer.
Group B Prediction
Winner: Roger Federer
Runner-up: David Ferrer.
Djokovic vs Ferrer. Winner: Djokovic
Federer vs Murray. Winner: Federer
Djokovic vs Federer. Winner: Federer