Federer didn't play well because Nadal put too much pressure on Federer to make awesome shots. Rafa chases down every shot and Federer kept going for more and more. Then the last set his 1bh broke down.
2007 AO vs. Roddick
I loved that match also because Roddick just beat Fed in a tournament that didnt count and said he felt that he was closing in on Federer. That set the perfect atmosphere for the beating.