The Shanghai Masters Cup starts today in what should be a fascinating men’s tournament- unlike the women’s event currently being held in Doha.

Even with the withdrawal of world No.1 Rafael Nadal, the tournament still looks to be full of intrigue with the game’s top players over the past 12 months involved. 

Roger Federer, Andy Murray, Gilles Simon and Andy Roddick make up the Red group and Novak Djokovic, Nikolay Davydenko, Jo-Wilfried Tsonga and Juan Martin del Potro compete in the Gold group.

Each will play three group matches and the top two will move through to the semi-finals, where the tournament will become a straight knockout event - much to the relief, I suspect, of many tennis fans.

So let’s have a look at the players in more detail and their chances of winning this prestigious event. Without Nadal in the draw, Federer becomes the top seed. He has won this tournament four out of the last five years and reached the final in the fifth, losing in an epic to David Nalbandian.

He loved the tennis surface in Houston, where the tournament used to be held, but his record in China is second to none and many fans will have him as their favourite yet again.Five out of six

Although not as dominant as in past years, Federer has still had an excellent 2008 by anyone's standards. He has reached the last three Grand Slam finals, including a win at the US Open. And he recently won an indoor tournament in Basel, showing he is in terrific form and ready to defend his title.

Federer's main group rival will be the ATP's form player at the moment, Britain's Andy Murray. This is the first time the Scot has qualified for the season-ending championships and he is ready to continue his dominance in recent months on the tour.

Murray has reached a career high ofNo.4 in the rankings and knows if he goes far in this tournament he could edge closer to a top three position at the beginning of next season. He has won five tournaments this year, including two Masters Series events and has also reached his first Grand Slam final, losing to Federer in the US Open.

However Murray has a good record against his Swiss rival, having won three of their five meetings, including the last in Madrid back in October.

Murray is playing with a renewed confidence and if he doesn't let the occasion get to him, could well win all three matches and finish top of the group.

However, like Federer, Murray will not have an easy passage as he also has to face Andy Roddick and Gilles Simon in the group. Former world No.1 Roddick has had another consistent year and deserves his place amongst the elite players. He has a 2-4 win/loss record against Murray and an even worse 2-15 record against Federer, so will have to prove he is at his best to reach the semi-finals. 

Simon reached the Masters Cup only because of Nadal’s withdrawal, but do not be fooled by the slight figure of the young Frenchman. He’s a player who is improving - and improving fast.  He has won two ATP tournaments in 2008 and recently reached the final of the Madrid Masters series, losing only to Murray. 

This year, Simon has wins against all of the top three and if he puts his complete range of skills into playing confidently this week, he could cause a few surprises.

In the Gold group, the top seed is Novak Djokovic, the world No.3. The young Serb had a brilliant start to the year with the first Grand Slam victory of his career in Australia - and has backed that form up with a consistent all-court display throughout the season.

He has won Masters Series events in Rome and Indian Wells, and has the ability to win in China this week. However, his form on the indoor circuit has failed to materialise and this tournament could be one too many in 2008 for Novak, who I think may struggle to qualify for the semi-finals.

Last year at the same tournament Djokovic lost all his round-robin matches and although he should be more competitive in 2008, his rivals are probably in better form than he is.

Nikolay Davydenko is something of a see-saw player. One minute he is brilliant and then poor the next. However, he has a serious chance of qualifying for the semis this year, especially if he can continue his form he showed in Paris last week, where he narrowly lost in the semi-finals to Nalbandian.

Davydenko has a winning record against Djokovic and I think if he can keep his serve together through the tournament, then he could well make the semis. 

 Tsonga is my pick to top the Gold group. The likeable Frenchman is full of confidence after his Masters Series victory in Paris last week. He is probably a lot fresher than most of his opponents in the draw after missing some of the season with injury.

He likes the big occasion and after losing to Djokovic in the Aussie Open in January, Tsonga has inflicted revenge over his Serbian  rival twice in the last two months and will go into their clash brimming with confidence. I think he could really make an even bigger name for himself in Shanghai.

The final player in the group is Del Potro. Again out with injury for parts of the season, the Argentinian has been in fantastic form in the latter half of the season, winning four titles in a row on the ATP tour - in Stuttgart, Kitzbuhel, Los Angeles and Washington, before losing to Murray in his first Grand Slam quarter final.

However, Del Potro though has never been so much in the limelight during his career and may find it tough to compete against more experienced players. After all, he has only just turned 20. I think Del Potro's time will come - but 2008 will be too soon.

My predictions for the semi-finals are Murray, Federer, Tsonga and Davydenko.  From then on it’s anyone’s tournament with all four capable of winning the Masters Cup.

However, it’s hard to bet against Federer with his record in this tournament - and if I had to pick, then it’s the Swiss Master who would get my vote!