Tennis legend Roger Federer now owns the record for most weeks all time spent as the world No. 1. There is no doubt he would love to finish the year at the No. 1 spot for the sixth time in his career.
He currently maintains that top spot. In the rolling rankings he leads world No. 2 Novak Djokovic 11,805 to 10,470. However, he is currently second place in points acquired during the 2012 calendar year. He trails Djokovic 9,910 to 8,905.
Federer is likely to enter the World Tour Finals with his No. 1 ranking intact. He won the Tour Finals in 2011, which means he has already locked in 10,405 points that he will carry into that event. Nevertheless, failure to repeat that victory could easily cause him to lose his No. 1 ranking at the last tournament of the year.
Federer's performance in three key tournaments will dictate who finishes the year with the world No. 1 ranking.
Federer is currently carrying 1000 points from his 2011 Paris Masters victory. He has had an impressive showing at Masters tournaments in 2012, already winning three of them. If he fails to reach the finals at Paris, this will cost him at least 640 points. It is important that he duplicate his success at the final Masters tournament of the year.
The Shanghai Masters tournament is Federer's biggest opportunity left this year. He is not carrying any points from that event, so any performance (even a first-round loss) will improve his ranking. He can acquire up to 1000 points there this year.
The last key tournament for Federer this year is the Swiss Indoors at Basel. This is one of three ATP 500 titles that Federer is carrying, and the tournament is held in his home country. Defending his title at Basel will help him maintain his position.
Overall, the race at the end of the year looks to be very close between Federer and Djokovic. Federer is carrying the maximum number of points (1500) from the final tournament of the year. Thus, if he is going to lose his world No.1 spot, that is where where it will most likely occur.