A number of thoughts:
1) I think the 1st set was too easy and Fed let his foot off the gas - big mistake.
2) As in other big matches he's lost, Fed's serve was sad - like the AO final the fact that he could get it to 5 sets when serving that bad is a tribute to the rest of his game.
3) Fed just couldn't get the ball away from the big FH
4) Again like the AO final, Fed came out tight to start the 5th, got behind, and couldn't recover
But great job by JMDP to not give up after getting pwned in the 1st; excellent serve strategy to go for a higher % so Fed couldn't attack his 2nd; and for having the new nastiest shot on the tour - his huge FH.
Shame on the fans: the constant yelling was pathetic - idiots who thought they were helping their man ended up hurting him. And Garner didn't do a very good job trying to shut them up. I think he's a one major chair ump wonder...