Were you on settler difficulty?
Or were the backwards civilizations Germany or America (they always do poorly).
The biggest WIN I can think off the bat would be playing America on the Earth18. Taking Montezuma on alone when he has a better starting position as a poor leader isn't easy. Then I cottage'd all of North America, tech'd up, and this is my favorite part: I made contacted with the old world...and they were ALL THE SAME RELIGION. A few turns later, the entire world declared on me; but I rolfstomped them with a massive stack of Armor-raze-move-on.