At least your first was on a standard run. I had to do the damn thing for the first time on AoMr and, yes, those Arch-viles scared the hell out of me. (Or into me, depending on your view.) I was so glad I saved the invuln from the previous level, it gave me the chance to kill one before I started taking damage.
For those of you who want an idea of how to handle them:
There are only two Arch-viles and they are on the very left (top and bottom) of the first big room. Rockets should let you isolate them before dealing with any other monster.