Rafael Nadal's world number 1 ranking is safe through Melbourne Park and if he is to be caught it will have to be in the longer term.
Roger Federer, the defending champion at this year's Australian Open, cannot directly catch Rafael Nadal for top spot on tour with the Melbourne Park results. Nadal, heading into the Aussie, leads Federer by over 3000 ranking points and that is a lead that will have to be chipped at in the longer term.
Here are the ranking points that are associated with each round in a Grand Slam:
Champion: 2000 (Federer's 2010 Australian Open result)
Quarterfinalist: 360 (Nadal's 2010 Australian Open result)
4th round: 180
3rd round: 90
2nd round: 45
1st round: 10
Even if Federer won the 2011 Australian Open his current ranking points total of 9,245 would not go up. The 2000 ranking points he would earn for the result would simply replace the 2000 rankings that drop off as the points associated with last year's title expire as the new points come in. The net gain/loss, should Federer repeat, would be 0.
If Nadal lost in the final he would earn 1200 ranking points and with only 360 dropping off from last season, he would have a net gain of 840 points.
In short, if Federer beat Nadal in the final, the world number one would still increase his lead in the rankings as ranking changes in the ATP are affected by, not just this year's result, but the net gain/loss between last year's event and this year's.
Nadal's ranking is safe at this point and unless someone can put a dent in his lead during the clay court season it should be safe until the summer.
However if Federer were to lose in the quarterfinals or earlier, for at least a net loss of 1640 ranking points, then there are players that could ascend to the world number 2 position with the January 31st rankings. Federer, if he lost in the quarters, would then have 7605 ranking points and Novak Djokovic or Robin Soderling could catch that total.
With an optimal result Djokovic, who has won the Australian Open before, could gain 1640 ranking points which would give him a total of 7880.
World number 4 Robin Soderling, the recent ATP Brisbane titlist, needs only to play in the Australian Open this year to 'defend' his 10 ranking points from last season. Soderling crashed out in the first round of the 2010 Australian Open to Marcel Granollers as the Swede continued his poor form from down under. If he, Soderling, were to win the title, an unexpected event for certain, and Federer were to lose in the quarters, or before, then Soderling would surpass Federer in the rankings.
Andy Murray, if he wins the Aussie this season, would only gain 800 ranking points, as he was a finalist from last season, and he could not catch Federer in the rankings nor could any other player besides Soderling or Djokovic, provided that Fed makes the quarters at least.
Scenarios are always plentiful prior to the start of a Slam and the permutations cannot be explored comprehensively. However from Federer's point of view at month's end it looks like he will be ranked either 2nd or 3rd if he makes the final 8 in Melbourne.
The 2011 Australian Open draw will be available on Friday January 14th with the tournament commencing on January 17th.