Vale brushed Stockport aside like they just weren't there in a 5-0 masacre.
Sean Rigg started the rout on 23 minutes, poking home from a long ball in a crowded penalty area.
Things got worse for County when Assoumani was sent off just before half time, being the last man (well, and bringing down Justin Richards). Marc Richards made it 2-0 from the spotkick, sending the keeper the wrong way.
Richards then made it 3-0 from another penalty after Rigg was bundled over on 62 minutes. Although the keeper guessed that Richards would again put it to his left, the kick was far too good for him, right in the top corner.
As Stockport ran out of puff, Justin Richards scored late, jumping in when the keeper could only parry an awkward shot, and Jack Speight made it 5-0 even later, tapping in with County's defence in tatters.
Chesterfield mysteriously lost at home to Oxford, which puts Vale back at the top.