At my last competition, I entered full silver and open silver for smooth. For some reason, the organizers scheduled the events so that open silver came after closed silver scholarship (which was my most important smooth event). So I had 4 smooth single dances, scholarship and then another 4 single dances. And for the second set my teacher decided to improvise more because a) we were already done with the scholarship and b) we could use this as an extra opportunity to do new standard material on a competition floor - since it was "open" silver, we could do that. So he told me that he will improvise and I should be ready for anything. And what do you know, my marks for that set were better than for the previous set or even the scholarship, even though in addition to the new standard material he lead drops and backbends we're not allowed to do in closed silver. When I commented to him about this, he said "it's because you weren't thinking, you just danced"
It must have been in the air, b/c at the same comp, my teacher led me into stuff I've never done before, in the open silver smooth. And I, too, was not thinking -- to get back on topic, I never think on the floor, other than, more or less, "Here's my teacher; ain't he cool?" If I'm presenting him, I don't have any room in my head to worry about me.
I have to try that as well. I think having open silver after the closed scholarship sort of took off the pressure to make it another practice round for the main event.