There are four tournaments remaining on the ATP's 2012 calendar and Federer is the defending champion at three of them: this week's Swiss Indoors, the BNP Masters in Paris and the ATP World Tour Finals.
That's a lot of ranking points to protect when he's just 195 points ahead of Novak Djokovic. Federer has been ranked No. 1 for 301 weeks, including the last 16.
Those five have qualified for the ATP World Tour Finals although Nadal is injured, leaving four spots available for the eight-player invitational in London.
The points for qualifying for the finals are calculated differently than rankings points.
Tomas Berdych is sixth on both lists but No. 7-ranked Jo-Wilfried Tsonga is eighth on the finals chart. Juan Martin del Potro, ranked eighth, is seventh in the tour finals standings.
With so much at stake, six of the Top 10 players are in action this week. Federer and del Potro headline the Swiss Indoors and Ferrer, Tsonga, Tipsarevic and Monaco are entered in the Valencia Open in Spain. Almagro is also playing in Valencia and Gasquet is at the Swiss Indoors.
There were three ATP tournaments last week. Berdych defeated Tsonga Sunday in winning the Stockholm Open in Sweden, del Potro won the Erste Bank Open in Austria and Andreas Seppi took the Kremlin Cup in Moscow. While the others didn't see their rankings change, Seppi goes from 25th to No. 22 this week.
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