[MunchkinMan]

No, it was not the correct ruling. The rules say that unless you defeat all the Monsters in a combat, you do not receive any rewards. This could be overridden by a card, of course, but the card specifically must say that it overrides that rule. Friendship Potion is pretty specific about what happens after it is played and doesn't say you get any rewards from any Monsters you may have defeated before it was played.