How did that happen? The team didn't make 500 until this season. They were not contenders.
It happened for two reasons: fans came prepared to have fun and the people selling to fans decided to put intention and influence behind creating fun for the fans. None of these people can influence the outcome of a single game: collectively, they have turned Toronto FC into a club whose fans are a force to be reckoned with.
Think about it. Influence the part you can influence. Create an atmosphere where everybody intends to have fun. Sell all the tickets - early.