There are a lot of small calls one could make on the board today as upset picks if they felt inclined: Butler over Wisconsin is tempting, as is BYU over Florida. But let me go right to the biggest team playing today: I think Arizona has a chance to topple Duke.
Most teams don't have someone who could match Nolan Smith bucket for bucket, but I'm not sure anyone in college basketball can stop Derrick Williams without doubling him right now. Duke is obviously always a hot team, but Arizona has won 14 of 17, and one of those losses was in double overtime. The biggest question for me about Duke right now is if they'll successfully be able to work Kyrie Irving back into the lineup. That went well against Hampton, but not quite so much against Michigan in the Round of 32. It's awesome to have a player of Irving's raw talent, but after these guys had jelled for a whole season without him, it's also tough for everyone to get used to their new roles.
Throw in that Duke is travelling all the way to Anaheim, which isn't much of a jaunt for the Wildcats, and I think they can keep it close. At that point, all they need is the same sort of pixie magic they had against Texas and for the officials to not favor the Blue Devils (I know, it's asking for a lot.)
I certainly like Arizona to cover the spread, if gambling were legal where I live, of nine points in Duke's favor. I think they have a decent chance to win as well.