Let me give you a striking example from one of my games on the Jebus map with a rather strong European player. The point is that HE, having a hero Caitlynn with stats 9, 9, 15, 133, with Stone Skin and Healing spells in her spellbook, on day 125, with ONLY 3 Archangels in his army (no other troops at all!!), defeats his enemy's army of 26 Ghost Dragons and, on the same day, defeats my army of 73 Manticores with an upgraded stack, all without any losses, and still has about half of his mana left...
P.S. Divide and conquer :)