I interview a ton of candidates, and my first call with them always includes the question "Why did you leave your last job?" Come to think of it, I have never seen a candidate get hired without having to answer this question. Not even once.
So get good at explaining why you left. Your interviewer doesn’t want all the gory details about why things didn’t work out in your last job. But the hiring company's due diligence requirements compel the interviewer to ask – and you should have a brief, logical, professional answer that reflects well on you and your former employer. When in doubt, be hard on the issues and soft on the people.
Ideally, you should get something in writing from your former employer. This brief letter should focus on the positives, even if you left for performance reasons. You might have to negotiate such a statement, but a written statement is a "must" – especially since your former bosses might themselves quit at some point in the future, leaving you with no record of your accomplishments during your employment there.
