First, create a game with the Lord of Lies quest (last quest in Act 2)
Clear your way to the mini-boss on the way to Belial.
You can outrange this mini-boss if you stand just close enough so you can see his feet on your screen. The missiles he fires at you won't reach you this way, and he won't move either. If you can clear your way to the mini-boss, it could become easily farmable in Inferno.