The 2012 season has been the first time in nine years that the Grand Slams have been shared between four different players. Back in 2003, it was Andre Agassi, Juan Carlos Ferrero, Roger Federer and Andy Roddick. This year it’s been Novak Djokovic, Rafael Nadal, Federer and Andy Murray who’ve shared the spoils.

In my opinion it’s been a refreshing change to have no single player dominating.

The season has been full of many fascinating subplots from the resurgence of Federer to the emergence of Murray as a player capable of delivering on the biggest stage. So for a change, we’ve reached October and the world no 1 ranking isn’t already tied up till the end of the year.

Currently, Federer’s in pole position but there’s plenty of eventualities which could take place over the next 6 weeks. Federer’s chances

By winning Wimbledon, Federer achieved his long-time goal of breaking Pete Sampras’ record for the most weeks as world number 1.

If the Swiss can cling on to the end of the year, it would be some achievement for a 31 year old.

Federer’s currently in pole position with 11,805 points, 835 ahead of Djokovic with 10,970. However despite his expertise indoors, Federer faces an extremely stiff challenge as he has a mountain of points to defend from 2011 in the coming weeks – 3000 in total.

A year ago, he finished the season with an astonishing run, claiming the Basel, Paris Masters and ATP World Tour Finals titles.

Djokovic and Murray are entered for all three of those events this year so Federer will have to be at his very best to repeat the feat.

However don’t bet against him. Federer has won Basel five times and he’s enjoyed an unparalleled level of success at the end of year eight-player extravaganza, winning the event for the past two years and six times in total.

His rivals will have their best chance of unseating him in Paris where his record is surprisingly poor.

However the organizers have been speeding up the courts in recent years which can only favor the Swiss. Djokovic’s chances

Twelve months ago, Djokovic was a broken man after his near superhuman feats earlier in the season – winning 3 Grand Slams, five Masters 1000 titles and going unbeaten for the first five months of the year.

As a result, the Serb has precious little to defend for the rest of the year and Murray admitted that his close friend is the most likely to end 2012 in pole position.

And as Djokovic showed last week in Beijing, his game is in fine fettle.

Expect him to mount a serious challenge to Federer in Basel, Paris and London, all events he’s won in the past. Murray’s chances

Murray’s US Open triumph fulfilled a childhood dream.

Now can he achieve the arguably tougher feat of becoming the first British player in the Open Era to top the world rankings.

"Yes, he can do it,” Federer told the press in Shanghai earlier this week. “He should be able to have that goal.

He has results that back up his chances. His next nine months are going to be extremely interesting to follow. I hope for him he can achieve it eventually."

"I think maybe at the end of the year, maybe the beginning of next year.

Or, if not then, he's got a shot until next Wimbledon almost - if he were to win there."

Murray is currently 3,715 points adrift of Federer so either he needs the Swiss to have a bit of a mare in the closing weeks to overhaul him, or he needs to produce some special results himself.

The good news from Murray’s perspective, is that his only significant points to defend are from last year’s Shanghai Masters triumph.

However he has a history of finishing the season on a bit of a downer. His records in Basel and Paris aren’t the best although he has made the semis twice at the ATP World Tour Finals. Predictions

I think we’ll see Djokovic come to the fore over the closing weeks and although Federer always performs strongly indoors, expect Djokovic to snatch two of the three titles the Swiss is defending.

So Djokovic to finish 2012 as world no.1 with Federer in second place.

Not expecting big things from Murray, his incredible summer has taken quite a bit out of him mentally and he didn’t look particularly sharp in Tokyo. However he’ll be a huge contender for the Australian Open title.

He’s come close twice in the past and now he knows he’s capable of beating Federer and Djokovic over five sets when it counts.