ggll
ggia
At least try to push him into a corner. Use some kind of spikes to disrupt the Phantom. If you don't have Fire, use Thunder. The barricades should be placed and destroyed by a close-range shot from the Arabs; not all of them, but you can take out the remaining ones with one peasant and have the rest attack.
In general, sometimes you have to admit that there are unwinnable battles. But you can save the game, think about it later, and maybe someone will come up with a solution.