Federer finishing power nails Nadal
World No 2 Nadal, unlike his rival, did not have the benefit of a day off before playing the world No 1, having beaten Nikolay Davydenko in his last round-robin game on Friday.
Federer reeled off three aces in the first game to set the tone.
After losing five consecutive matches to Nadal, he has won their last two, including in the Wimbledon final.
He said: I'm happy I came through because these are the matches I'm waiting for, to beat the best after me.To beat him in the last one of the season is fantastic for me.'
In the final, Federer will play American James Blake,who beat defending champion David Nalbandian 6-4, 6-1 in the semi-final.
Blake beat Nadal and No 3 Davydenko in his round-robin games. He broke Nalbandian twice in the first set and three times in the second.
