They were better because they consistently made those shots. Miami played awful perimeter defense, as has been the case all season. Virginia made the plays they needed to make.
This loss hurts, not because it was a bad loss(It wasn't), but because it was a missed opportunity. Miami had a chance to steal a road win over a ranked team and clinch a NCAA Tournament bid, and didn't make winning plays late. Good teams find a way to win these games, because winning today can possibly be the difference between playing in the 8/9 game or a 7/10. That said, as long as Miami takes care of business against the teams they should beat(BC, FSU), then this is a mere hiccup..