PvP strength and Baal damage are not synonymous. Someone can easily be strong in one and not the other.

Power is a rough gauge of a player's total hero strength, but is not too important in Baal. For example, a Vitality rune would give you a great deal of power, but because Baal kills any hero in one hit, it offers no benefit during this encounter, even though your power would be higher while wearing it.

Hope that helps and good luck!