Playing like that, they probably lose with Jefferson. But hard to say how exactly it would have gone.
As is, without Jefferson, ISU doesn't have a single NBA player in their rotation. And if I'm brutally honest, I think Jefferson is probably borderline NBA. I hesitate to call anyone "great", despite the objectively successful year.
Tennessee turned out to be a bad matchup. ISU had to make shots and just didn't. Usually the one saving grace when the team is missing shots was stealing extra possessions through turnovers, but that advantage was entirely negated by losing the rebounding battle by 20+. Add in this being one of the worst D1 free throw shooting teams I've ever seen, and you get the result.