Hello!

It would be possible that there's no one else playing the Arena when the time you were playing. It's still in the early weeks of the months and only a few play the arena during that time from my experience or from my region. On the other hand, if you keep getting matched with the same person and losing all the time, then you should know that you have to stop for a while or build a better team to counter him or her. Also, BP isn't relevant in the arena but Initiative. Thank you.