Aziraphale and Crowley being angelic and demon everymen, respectively, is very good, if not quite low on any sort of totem pole, but possibly better is Aziraphale and Crowley both being significantly more powerful than either of them realize – probably more than their bosses realize.
There are infinite possible mechanical explanations, if you want. Angelic/demonic power is kind of like a muscle, and they exercise it far more on Earth than anyone does in Heaven or Hell, either because they just do more or because it takes more effort to do the same thing (moving through water vs air.) Proper angelic power is based on love and fallen angelic power on hate, which as we know is almost the same thing, and over 6000 years with humans, Aziraphale and Crowley have developed a whole lot more of both than anyone else. Maybe it’s that they intuitively understand more of the Ineffable Plan than anyone else, even if they don’t realize it, and that counts for something. Or maybe there’s just been a lot of Discworld-style belief invested, over the millennia, in the only two supernatural beings any human actually met. (Particularly, tbh, mythologically, in the Snake. Aziraphale needs to keep up.)
They could probably singly and certainly together kick the ass of pretty much
anyone in Heaven or Hell. Not all of them at once, though. Unfortunately.
Juli Fusina and More 