lets say is level based but for how the queues work it's like if level or power don't matter.

If your enemy is at his first time can meet you regardless what you did before if you are lower level or par level and lower power than him.

If your enemy is in queue when you click on 'match' since more than 60 seconds and you are the first after the 60 seconds passed to click on 'match' you are instantly matched with him regardless your previous fights.

If your enemy lost his previous match and was in queue before you and you click on match while being lower power on par level or lower level then you are instantly matched with him regardless what you did before.