No, Biden had never won a single primary (while Bernie had multiple during this campaign alone) until SC, when most every other candidate dropped out while endorsing Biden in a span of a week or so in a (successful) attempt to deny Bernie the nomination.

And then there are things like the Iowa caucus where Mayor Pete decided to crown himself winner before one was officially declared (gee, sound familiar?) because the Iowa Dem party crapped the bed.

Bernie only won a single primary, Nevada, prior to South Carolina. He lost in Iowa and tied in New Hampshire. Just prior to Super Tuesday several candidates who were polling in single digits dropped out and endorsed Joe Biden. Maybe it was because they agreed with Joe's policies, maybe the party put a gun to their head, and maybe they just didn't like Bernie.