Can I just play one round online? Is it always first to three wins? Because that takes FOREVER! Thank you

It is always best 2 out of 3

On the PSP version, if you host you can pick your own scheme, so you can make a scheme with only 1 round if you want to.

The DS version uses random scheme and rounds in ranked games. In a random game/friends/rivals game, you can vote for the scheme.