Some of you older guys (I'm pushing 40) can maybe tell more and add to this but it seems USC and NC State have had a pretty good relationship.
I saw we played NC State yearly in football from 1956-1991 (except 1967 which I assume was a conference scheduling issue...long before my birth). What I thought was interesting was we dropped out of the ACC in 1971, yet played them for 20 straight years (until we joined the SEC)...and remember some dog fights in my youth (80s).
While some schools were mad we left the ACC, it seems like NC State probably understood our perspective and wanted to keep a good relationship with USC, thus continuining the football rivalry. I guess we could find coming ground in our hatred for Clemson and North Carolina.
Having said that, I hope we beat the crap out of them in a few weeks.