US Open Tennis 2009 Winner is Federer vs del Potro

The US Open Tennis 2009 is already at the finals today, September 14... and only hours from now, the winner will be announced. The Men's Singles is between Switzerland's Roger Federer and Argentina's Juan Martín del Potro. Who will win between the two? Is it world's best Tennis player and depending champion currently the #1 seed, or is it the challenger Juan Martín del Potro.

Here's the partial result of US Open Tennis 2009 Men's Singles (winners are in bold):

Quarterfinals
Roger Federer vs Robin Soderling
Novak Djokovic vs Fernando Verdasco
Fernando Gonzalez vs Rafael Nadal
Juan Martin del Potro vs Marin Cilic

Semifinals
Roger Federer vs Novak Djokovic
Rafael Nadal vs Juan Martin del Potro

Finals
Roger Federer vs Juan Martín del Potro