i just built the latest mainline nginx from source on fedora 21 (64bit) and when i run: service nginx start

i see:

Redirecting to /bin/systemctl start nginx.service
Failed to start nginx.service: Unit nginx.service failed to load: No such file or directory.

i've searched around online and so far found no-one else reporting the same issue.
i think i have fixed this before on another installation in the past.. but presently i'm not sure what the resolutioin is - can anyone help?