Board Thread:Battle Nations Discussion/@comment-25765999-20150912063834/@comment-25584573-20150913081054

Top priority for selecting opponents is a IP filter (opponents must come from different IP spaces), then the player lvl is considered. Only if more than one other player is left the PvP value gets evaluated.

Try it yourself: Arrange a fight with your friends located at the same provider - you will never get him as opponent, even when no other is ready. Arrange a fight with exactly the same units at the same rank but different lvl (more than about 8 difference) - you'll never meet him in random PvP.