O2 be crowned king

All eight desire it, but only one man can become ATP World Tour champion. Here's Barry Cowan's preview.

Great eight line up in London to battle it out in showpiece finale

Andy Murray and the magnificent seven are ready for the final showdown - and Sky Sports has every angle covered. In what promises to be a thrilling climax to the season, the globe's best players will bid to become ATP World Tour Finals champion from Sunday and skysports.com will bring you the latest reports and results as the battle unfolds. Tennis live on Sky. The competition, formerly known as the Tennis Masters Cup, pits the 'great eight' players together with an impressive prize fund of $5m on offer. Here Sky Sports pundit Barry Cowan gives his thoughts on who will take London's O2 arena by storm...

Roger Federer

The Swiss has enjoyed another amazing season, reaching his 22nd consecutive semi-final or better at a grand slam and he is now chasing his fifth title at the World Tour Finals. He enjoyed a long break after the US Open and should still be well rested. Although Roger lost to Novak Djokovic in the Basel final earlier this month, he played well to get there and last week Frenchman Julian Benneteau had to produce the match of his life to beat him in Paris. So Roger is my favourite to win the title. His movement and speed are as good as they've ever been and the motivation to win in London will be as strong as ever. Of all his weapons, his serve is the biggest. If he serves well then confidence spreads through the rest of his game. During his difficult period earlier in the year, when he lost high-profile matches, around 50 per cent of his first serves went in; at his best he's above 60 per cent, which he achieved in both the French final and the Wimbledon final.

Rafa Nadal

Even after an injury-hit season Rafa still has an outside chance to end the year as No 1 for the second successive year - but the Spaniard will have to win the event and hope Federer performs badly. Rafa hasn't won a title since Rome in May and although it's not exactly a crisis, the longer he goes without one the harder it can become. His performances have been very consistent since he took a nine-week break and reached a quarter-final on his return to action in Montreal in August. Since Canada he has made four semi-finals and a final in Shanghai, where he lost to Davydenko. But Rafa has struggled against the top 10 players in the world; he has lost five matches against the elite and only beaten Jo-Wilfried Tsonga, last week in Paris. While he clearly is not at his best, Rafa's desire is as strong as ever and he won two matches last week on pure determination alone. Physically he's strong but the confidence is not as it was seven months ago. You can never write off a champion, but I feel we won't see the very best from Rafa until Australia - and not in London next week. When he is not at his best he plays too far back behind the baseline on a hard court and his forehand especially can be hit with too much spin.

Novak Djokovic

I'm so pleased Novak won in Paris last week because his consistency has been phenomenal this year. In his last 20 events he has won five titles and has only failed to reach at least the last eight only once at the French Open. But before last week's victory in Paris he hadn't won a big title for 18 months. Now that his run has ended and, as long as he's recovered and is as fresh as he can be after a long season, he is the form player going into London. He crept over the line in the final against Gael Monfils in Paris after leading 6-2 3-0. He lost confidence in his forehand but in the deciding set tie-break he still had the belief to hit the stroke and this was crucial in him winning the match. The defending champion has played a staggering 94 matches and has won 76 of them - proving on the way that he's an incredible athlete. With added confidence he plays more aggressively and the backhand is a world-class shot, especially down the line. When the forehand is firing only Federer can currently beat him indoors on a hard court.

Juan Martin Del Potro

It has been an amazing year and whatever happens next week the Argentinean can look forward to next season; he simply needs a break to cure his ailing body and rest his mind after what has happened since winning the US Open. He has only won one match, against Marat Safin last week, since his victory in New York. In the following round Fernando Gonzalez retired in bizarre circumstances after Juan Martin had pulled his stomach muscle. Juan Martin then retired against Radek Stepanek. In his three losses, he's retired twice and has lost to a player ranked 189 in the world. Juan Martin won't be 100 per cent fit in London so I don't see him getting through the group stages. He is a class player and he will regroup after the season and will make another charge midway through next season. His big first serve and strong second serve are the main reasons he has become a Grand Slam champion but doubts persist about his stomach injury. For a tall man he moves very well and his forehand in the final in New York was the best ball striking I've seen this year. He now has no weakness but with the expectation on him, it will be difficult next week.

Nikolay Davydenko

I've started to call the Russian 'The Wall' because he is relentless and the ball keeps coming back with interest. Nikolay is making his fifth consecutive appearance at the World Tour finals and last year he beat Andy Murray in the semi-finals. He's followed up this year by winning four titles, all of which have come in the last five months; not bad for a player who missed the first three months of the calendar with a heel injury. His movement is comparable that of the top four players in the world and when he's confident and is playing his best tennis he can beat anyone with the exception of Federer, who has won all of their 12 meetings. He has also improved his net-court game that has enabled his game to keep evolving The reason he hasn't won a Grand Slam is his inability to win big matches when he isn't playing his very best tennis because his defensive game isn't as good as the top four. Recently he has lost to Safin, Robin Soderling and Mikhail Youzhny because all three were able to match him on the baseline.

Robin Soderling

The Swede has really emerged this year as he's matured on and off the court. He has always had the firepower, with a great first serve and strong ground shots, but the perfectionist side to his nature meant he used to get very frustrated in the big moments. His new coach, former world No 2 and former French Open finalist Magnus Norman, has helped enormously. It is clear that Robin has a lot respect for his coach which has helped him at key times. Earlier this year he was the first player to beat Nadal at the French Open and made it to his first Grand Slam final. Robin only secured qualification for London after Andy Roddick pulled out with injury but his game is well-suited to indoor tennis and he could be the surprise package if he can cope with his first World Tour final appearance. A real plus is that he will believe he can win the event. Before the start of 2009 he had won three titles and reached another six finals and they were all indoors, but this year his only title came on the clay in his home country. His movement has improved this year but the top players can expose his lack of speed and change the tempo of the rally.

Fernando Verdasco

He has turned around his career since clinching the Davis Cup for Spain in Argentina nearly 12 months ago. This win gave the Spaniard real belief and after working hard on his fitness with Andre Agassi's former trainer Gil Reyes he started the season in an explosive way by reaching the Australian Open semi-final before losing to Nadal in a five-set match lasting five hours 10 minutes. On his way to the semi-final he beat both Murray and Tsonga who were both in the top 10. Fernando certainly deserves to be in the top eight on the basis of his consistency in 2009; he has reached at least the last eight in his first eight events. But after losing to Nadal in Melbourne he has now lost his last 11 matches against top 10 players. He's found trying to qualify for London very difficult over the last month. He has struggled to cope with the pressure and looks jaded after a long year. His previous success has been largely down to his world-class forehand and he has also improved his first serve and cured his yips on the second serve too. His forehand has been suspect recently but I believe this is due to tension. Now he has qualified for London, he can go to the O2 and play with the free spirit he had at the beginning of 2009

Andy Murray

Andy goes into the World Tour finals as the fourth best player - just as he did 12 months ago. He's enjoyed a good year, winning six titles, and now has 14 career titles which include four Masters events. But I thought at the beginning of the year that he was going to win a Grand Slam and as it's turned out his best chance was at the French Open but, unlike Del Potro in New York, he failed to grab it. Andy won in Valencia after not playing for six weeks because of a wrist injury he picked up at the US Open. This enforced rest will help him going into next year as the last two years have been very intense, both physically and mentally. London is a very important tournament for him, though; he needs a strong showing to give him a mental boost going into the Australia Open in January. He had a decent time in this year's Grand Slams, reaching his first quarter-final in Paris and his first semi-final at Wimbledon, but Andy's career will be defined by Grand Slam victories. He turns 23 next year and must make the next step in the next 12 months. He has missed out in the majors this year because his opponents played more aggressively at the big moments - something he has to address. Andy certainly has the artillery to win: his backhand, movement and reading of the game are all world class. But he is a cautious player by nature - an approach that works when he plays against opponents who are playing well but not when they are at their very best. His matches against Andy Roddick at Wimbledon and Fernando Gonzalez at the French Open are such examples.