The two participants make an opposed roll of their POW. The loser loses d3 magic points. If he also made his roll, the winner loses one magic point. If there is no winner, no result occurs that melee round. If the winner criticals, the loser's magic points are reduced by d6.
When one combatant is reduced to zero magic points and the other is not, the victor can perform an appropriate action (bind a spirit, possess a person, etc.)
Example: A Passion Spirit attacks Suboti in spirit combat. Its POW is 13, hers 11. In the first round of spirit combat, the spirit rolls 8 and Suboti rolls 3. The spirit won the resolution, and Suboti loses 3 magic points. Since she achieved a partial success, the spirit loses one point.