That's the same as being "in the zone", isn't it? When your body is just doing the things it's supposed to do without needing you to instruct it, when the bat has arrived at the right place before you've consciously worked out where the right place is. As Louis Menand said of any golden age (and a Test Match hundred is a golden age), it's "the time when things work in such a way as to make you think they will work this way forever".
I suspect any form of performance must be pretty much the same. You can't act or sing or juggle if you're worrying about how to do it or trying to do it in a different way. Of all the adjectives that critics employ to show how much they approve of a particular performance the most inappropriate one must be "intelligent". The best performances are the work of an almost empty head. The intelligence was all used up in rehearsals.
That's why interviews with athletes are traditionally so unsatisfactory. They say "I put the ball in the right areas" or "it just came over and I hit it" because that's the truth. Thinking any more about it isn't going to make it any easier to do and they above all know how hard it is to do.