Easiest victory is simple -
Duel Map. Choose any civ except Enrico Dandolo. Set for quick. I like using archipelagos because it's easy to move cruise missiles and nukes around.
Turn off barbarians. Set city states to 0. Choose Information age. Turn off ALL victory types except DOMINATION. Do not set for complete kill.
You will start with 3 settlers. Because Enrico will have no city states to buy and cannot form new cities, you only need to wipe out his main city. If he starts near uranium, simply restart a new game.
Find the uranium deposits and build your cities next to them. Research satellites first to reveal the whole map (makes this part easy). Put all your policies into Rationality for the Free Tech when you get the next policy. With your free tech - take the one that gives you nuclear missiles and guided missiles. You will need ~4-5 nukes. Also, you will want ~3 missile cruisers, about 4-5 guided missiles, and 2 or 3 Xcom dudes.
Build up the above weapons then position yourself around Venice. Stay far enough back not to nuke your troops. Nuke Venice with all 4-5 nukes. This will take Venice to almost no defense and wipe out his troops. Move the missile cruisers (with guided missiles on board) and Xcom units next to the city.
On the next move, he will renew about 33% of his strength, build an artillery and a ship. Hit him with the missile cruisers and then the guided missiles. You Xcom dudes will then take the city and boom - Flawless Strategy. This was so easy it was boring.