Winning an audition is not about staying calm and avoiding mistakes. It's about presenting an impressive musical product, one that will not be hindered by nerves or adverse circumstances. You must be so confident in the musical message, that you are able to play it anytime and anywhere.
High quality playing however must be a constant focus. Otherwise you might not be able to withstand those pesky monsters that attack at every audition: fear, nerves, travel nightmares, poor warm up conditions, negative feelings, intimidation by competitors, self-doubt, a bad chop day, etc. Simply put, your constant obsession for outstanding playing must overpower any obstacles you will encounter. Think of your practice as bulking up on the music. Consider yourself an unstoppable musical hulk!
Picture a powerful horse pulling a child's toy wagon. The horse is your strong concept of the music. Trailing behind is the little wagon carrying all of your greatly dwarfed performance enemies. Those usual anxieties will no longer plague you when your message is stronger than your distractions. Since you can't depend on favorable conditions on audition day, you must fortify your musical product.
Your internals must defeat the external assaults. Be preparing yourself for your most convincing musical presentation possible!
The audition then becomes just another day at your future office.