I think it happens more often than not.   Any individual measurable sport it happens a lot. 
You go out on the next set and expect it to be the same or better and it doesn't happen.


Track and field, for example go out and throw/jump a PR. think "wow that was easy, what will happen if I try a bit harder"  the next thing you know you have some real bad throws/jumps."  You lose focus of the zone you were in. 

That part takes as much training as the event itself.  Ask any athlete that is at the top of their sport and they have experienced it, but they have also practiced enough that they can duplicate their technique more consistently then the rest of us.

I think the mental part really is where you can slow the "game" down to a speed that you can make changes in action that will correct an existing or upcoming error (however subtle or major it may be) before the next sequence of action occurs.

So congrats, and think about the 35 and what you were doing right, and what you were doing different on the 32's, replay in your head and try and figure out where you were doing something different.

Todd