This might be an example of a race where the candidate who leads in every poll (or almost every poll) loses. If Heck's not overperforming Trump by more than 6, he's done.
Heller wasn't really posting big leads in the polls but still held on.
He was leading in the polls by about 4-5%, and just barely held on, thanks to a large number of Obama voters voting "none of these." Masto is a far better candidate than Berkley, so Heck has his work cut out for him. This race is certainly more competitive than the presidential race in Nevada, but the way things stand right now, I would bet on Masto.