No they are not. He will most likely win for two reasons.
1. The trade were for virtual items. Virtual payments are not supported by paypal, so they will not fight the case for you unless you have a tracking number, in which case you do not.
2. Unauthorized means the payment wasn't approved by him. Although I'm sure he was the one who sent you the money, it's a common scam tactic used on paypal.
If you plan on using paypal in the future for virtual trades, trade with users who have credibility behind them.
