Be polite and keep a dictaphone running in your pocket. You will then have the evidence to counter any attack
Best advice: 1. Always be kind and respectful towards all your co-workers, no matter how they behave towards you. Remember, you are not responsible for anyones actions except your own. When you treat everyone you work with this way, no one will believe this guy when and if he starts talking trash about you. 2. When and if he does start being rude, call him on it in a very polite and non-threatening way. For example, let's say he makes a rude accusation or comment. Politely respond in a very gentle voice something like "Matt, help me to understand what you are saying....why do you say this?" Also, it helps to have a witness in these situations but just be careful, because if you cause him to "lose face" in front of others it will fuel his insecurities. Also, try to get as much of these "conversations" in e-mail. That way if he is rude, you can keep the e-mails as a record of his treatment of you to show your boss or HR.
Kill the individual with kindness!
Start being very friendly toward your boss also. Matt shouldn't be his only friend.