importance of MSc classification?

hi everyone,just joined this is my first post.anyways im currently doing an MSc but basically i screwed up one of my exams,and it will be difficult to now get a "commendation" and will probably end up with just a pass.How big a deal is classification of a masters compared to undergraduate?i know the difference between a 2:2 and a 2:1 is massive in undergraduate,but considering ive already gotta 2:1 MEng will only getting a pass at MSc put me at a big disadvantage if i want to get a job relating to it?im pretty sure i'll get a decent reference from my supervisor but am still a bit angry with myself for my exam results.

cheers

mick