It was really something else.
Federer was back on his heels in the first set, absolutely being dictated to, mostly because he wasn't getting his first serve in.
He got down in his first serve game of the second set, and it was like something clicked. Like a lightbulb went off.
He started moving his feet, taking the ball much, much earlier, running around to hit forehands, just generally ruling. And Nadal crumbled, started making errors. Had his ass handed to him in a way I don't think he ever even remembers happening on clay.
6-2 and 6-0 in the last two sets. Federer was pretty overcome. Even his usually-catatonic girlfriend was into it. They had a nice, tender moment afterwards, which you rarely see from him.
Now, best-of-5 sets is a bit of a different story. Nadal got a lot further the previous week's tourney, and he barely squeaked one out against Hewitt the previous afternoon. I think he was a bit run down.
But at least this makes it interesting. A week ago, Nadal was odds-on, and you wouldn't have bet on Federer not to get upset early by one of the multitude of Spaniards and Argentines as he looked too far ahead to Nadal. It almost happened twice - this week alone.