I too watched all of the performance. While I admire Willie greatly, the thing that I was most struck with (as others have mentioned) is his phrasing, both vocally and instrumentally. It's as if he's in his own little world completely oblivious to everything. He phrases every song as if he can't wait to finish it, which is somewhat unusual since many vocalists prefer back-phrasing as opposed to foward-phrasing. This is what gives him such a rushed quality, and the same with his guitar playing, which is so jazzy and Django on the one hand, and so utterly unique on the other.
If you were a musician in his band, not only would you have to know his entire repertoire in your sleep, but would have to always be listening and completely focussed (while appearing laid back), anticipate him on a breath's notice, and be telepathic as well.
He and the band, are in a word, extraordinary.