Sometimes when i practice, i use a metronome....
it may sound like it would be overdoing it, but once you have gotten a flourish down consistently , its much easier to get smooth.
Make sure you arent doing the opening slow, and then the second part(crabshack?)really jerky, or something like that.....
Its a common things to have nerves when performing in public, and it soemtimes puts a hinder on your skills, The only advice i have for this is practice....
Hope this helps!!