Right behind winning a Grand Slam tournament, the main goal for tennis players is to reach No. 1 in the rankings and, also, to finish the year in the top spot.
With the four 2009 Grand Slam events now ancient history, the year-end No. 1 is the biggest prize remaining.
On the women's side, it is between two players, Serena Williams and Dinara Safina. The Williams - Safina contest for the top spot has been widely discussed over the past few months, with controversy swirling around whether No. 1 should be a matter of quality or quantity.
Williams has the quality results with Grand Slam titles at the Australian Open and Wimbledon. Safina has the quantity numbers, having been in eight finals in 2009 to just three for Williams. Runner-up at both the Australian and French Opens, Safina won three of those finals while Williams's only successes came at the Australian Open and Wimbledon.
With just one event remaining for both, the season-ending Sony Ericsson Championships in Doha, Qatar, from October 27 to November 1, Williams is ranked No. 1 ahead of Safina by just five points - 7,945 to 7,940. (The WTA Tour rankings are based on a 12-month rolling system of results.)
But in a more relevant category, the Race to the Sony Ericsson Championships, which only includes points accumulated in 2009, Safina leads Williams 7,731 points to 7,576.
So, Williams will have to outperform Safina in Doha or Marat's little sister will end the season at No. 1, something her big brother never did.
That would no doubt spark heated debate because Safina did not win a Grand Slam title in 2009 - but she will prevail in terms of quantity over quality. Her overall record for 2009 is 55-15 while Williams is 45-12.
In favour of Safina, the rankings give ample weight to all the events played in a year, something that encourages players to perform well at the more than 50 tournaments that make up the WTA Tour.
In favour of Williams, everyone knows the Grand Slams are the epitome of competition in tennis. With Williams a winner at two of the four, and runner-up at a third, it's easy to make the case that she came through under the greatest pressure and should be rewarded with the No. 1 ranking.
The bottom line is that if Williams, given the huge head start she gets with the 4,000 points (2,000 per Grand Slam) she earned for winning Wimbledon and the Australian Open, cannot earn enough points at the other tournaments, she does not deserve to be No. 1. Safina is simply playing by the rules.
On the men's side, the top two positions are not wrapped up but every indication is that they will be as they have been for the past four years. In 2008, the order was Rafael Nadal No. 1 and Roger Federer No. 2, but this year will likely revert to the pattern of 2005-2007, with Federer finishing in the top spot and his Spanish rival in second place.
Nadal has a chance to catch Federer - the Swiss leads in 2009 points by 9,855 to 8,245 - but he needs a hot streak and poor performances by Federer. He gets a chance to make up 1,000 points at this week's Masters 1000 in Shanghai, and without the resting Federer in the field.
Nadal's No. 2 spot is a virtual lock. About to be No. 3 (in next week's rankings) Novak Djokovic, Andy Murray, about to fall to No. 4, and No. 5 Juan Martin del Potro would pretty well have to pretty well run the table at the big-point events in Shanghai, Paris and next month's year-end ATP World Tour Finals in London to have any chance of ending the four-year Nadal - Federer monopoly of the top two positions.
AD OUT: It has been a good year for older women on the WTA Tour with the average age of the four Grand Slam winners - Serena Williams (2), Svetlana Kuznetsova (1) and Kim Clijsters (1) - being more than 26 years old.
In that same vein, there is a match-up of two positively senior citizens in the first round of this week's WTA Tour event in Osaka, Japan, when 39-year-old Kimiko Date Krumm of Japan, ranked No. 101, is matched against American Jill Craybas, 35 and ranked No. 83. Their average age is 37, outdoing the Grand Slam winners by more than a decade.
Also from the Osaka draw, another Wozniak - Wozniacki match-up is potentially in the offing. If top-seeded Caroline Wozniacki of Denmark and No. 6 seed Aleksandra Wozniak of Blainville, Que., reach their appointed spots in the quarter-finals, it would be their fifth meeting in of the year. Wozniacki leads 3-1.