It just goes both ways. I mean, the Seattle receiver kept his concentration too and made a great play with the bobble. Malcolm Butler made an unbelievable play too. They all made unbelievable plays. Pete Carroll was 99% certain that would work, was not expecting Butler to make that incredible play. If you recall Belichick was miked on the sidelines saying that Manningham would have to beat them on the outside, no one else. Same thing. Belichick is putting a 1% probability on that happening. And for Manning to even throw that duck to Tyree, a few things have to happen. Asante Samuel has to drop a sure INT on the previous play, and Manning has to somehow get out of the scrum.
Little plays, luck, astounding concetration, etc. This is how you win. It's how you lose.